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About the Borla muffler...

Merlin Johnson (

The Borla is full stainless with stainless packing and has a single round "intercooled" tip. It is a bit louder [than the Stillen] at full throttle but VERY quiet at freeway (60-75mph) speeds with no "droning". It gives around 15 (I know that number seems high, but I have talked to various people and they all come up with the same figures). The Borla gives a little more up top. The Borla muffler is $387.

Jon L. Peccarelli (

The Borla muffler is a straight-through type with holes in the muffler portion to "muffle" the sound. And it sounds AWESOME. The tip looks a lot like the stock one, except it is all stainless steel instead of just the polished outer cover of the stock one. The tip is much closer to the body (like 1/4" gap between the body and the top of the tip).

The muffler itself is much smaller than the stock one (and much lighter too). I had to bend my heat shield just a little bit and tape up the right rear tow point (the hook underneath used to tow your car) a little bit to keep it from rattling when I would corner hard. You can't see the tape unless you crawl underneath the car.

About the GReddy (a.k.a. Trust) cat-back system...

Peter Wu (

I used to have a Trust/GReddy, it's a cat-back system, not like Borla/Stillen, those are muffler only. The mid pipe is 2.25 inch I believe, has a 2.5 inch tip at the end I think, not sure, also, it was pretty quiet, supposed to be quieter than the Borla, however, it gets really loud at around 70mph on the freeways above or below tht it's actually pretty quiet. It's supposed to give +18hp but I doubt if it really gives that much. Mine got all rusted in about a year and a half (but I live near the beach) they only give a 1 year warranty (Borla has lifetime) so you might want to consider that too. I think price wise they are actually about the same. I got my installed for $400 at a place in So. Cal. That's all I know.

Thomas Paule (

I spoke with Millard Cook at GReddy (1-800-GREDDY2) concerning the question of GReddy vs. others exhaust. The Stillen (which I have) and the Borla are baffled. The GReddy exhaust is a straight through design with holes in the pipe. These holes open into the muffler that is stuffed with a "cubed" wadding made of composite fibers. These cubes absorb the sound, while the straight through design allows exhaust gasses a quick exit. The muffler han't been Dynoed yet, but expect a 5-10% increase in sound over stock at idle, and 15% more sound at full song. The sound level is EPA legal and within allowances for racing applications. Also the sound is a deep, and throaty, and may be available for listening soon, since I might get it for my SE-R (once it is rebuilt). List for this piece is $400.00. It is specifically designed for the 91-94 SE-R, and has a 2 inch pipe and a 2 3/4 inch single tip.

Kyle Gilliland (

I spoke with Tim May at GReddy (1-800-GREDDY2). He told me they had some problems with the mufflers rusting on them. In the past the piping and muffler were Aluminized steel. Now the piping is still the same, but the muffler is now Stainless. He said the reason they did this is the muffler is the always the first thing to rust...?? He said he is using a GReddy exhaust and has been for over a year, with no rust problems, he doesn't do anything to it and lives in the San Diego area. He said the new model with Stainless has been out for about the last 2-3 months and estimates the life expectancy to be around 5 years in harsh weather.

About the HKS cat-back system...

Merlin Johnson (

HKS makes a system (cat back) but only makes 7hp and costs more than the Borla. If you are fanatic about staying quiet, get the HKS system.

Fred Miceli (

I've got it also! Looks great, fits perfect, sounds great under full throttle without that droning at highway speeds (70mph). There was no noticeable power difference! It is all aluminized. I've had it on (I'm in NJ) for about 8 months and only the hangers look rusty, otherwise it still looks like it is in great condition. I believe that the single tip is 3" in diameter, it is noticeably larger than the stock tip and looks better. The piping is 2.25" outside diameter. When I looked at the exhaust, I could tell how well made it was, it has mandrel bends and the flanges were strong and perfect. The exhaust comes in two pieces, it is a cat-back exhaust, it looks great from the back, it comes with gaskets (no bolts though) and it fits PERFECT!!!

The HK$ is expensive though ($400). I bought mine back in the beginning of 1995 and I paid around $370 including shipping from Alamo Autosports in Texas (they were running a special deal). It was the cheapest place around. Right now, I am very satisfied with the HK$ exhaust and I would recommended it to anyone.

About the Stillen muffler...

Merlin Johnson (

The Stillen is an aluminized muffler with dual stainless steel tips. It is a bit quieter [than the Borla] at full throttle but VERY quiet at freeway (60-75mph) speeds with no "droning". It gives around 15 (I know that number seems high, but I have talked to various people and they all come up with the same figures). The Stillen muffler is $225.

About Supertrap mufflers...

Wayne Cox (

They SUCK on an SE-R! Had one on mine about 4 yrs ago. With 6 disks on it (for quiet) it choked the engine off worse than the stock muffler. Stack on 9 or 10 disks, and the noise was unbearable. Hell, it was too noisy even with the 6 disk setup. It's not a "good" noise either. Buzzy as hell. This was a full-length stainless steel 2.25 inlet one. If you want to know what it sounds like, unbolt your muffler at the back flange, take it off, and drive around. It is that bad... run away! run away!

About the Stromung cat-back system...

Wayne Cox (

I have the Stromung system from the now defunct GP motorsports. Stromung Exhaust Engineering (714.890.8052), is still in business somewhere in CA. It's a well built cat-back 2 1/8 inch mandrel- bent system, that still has the standard flange between then pipe and muffler section so you can mix&match pipe and mufflers (they will sell the pipe section separately I think).

It's kinda loud, but much deeper and not as "buzzy" as the Borla I heard on an NX2000 at an autox this last weekend. I also has these extremely cool looking huge 3.0in. dual stainless steel tips stickin out the back! I paid $320 - GP discounted it some from retail list. Combined with a POP style intake from GP it now pulls strongly all the way to 7500; used to fall of the peak at 6800 or so. Actual drag strip numbers were 15.31 @ 89.7mph!

It has a flange connection the same as stock, so you can combine the pipe with other mufflers, or only buy their muffler. It is also the only the Infiniti G20 exhaust that I know of.

Cat to Muffler pipe$130
Muffler with cool tips$245
Cat-back system$375

Between the Stillen and the Borla, which would a better exhaust be? Sound? HP? etc. Which of the two is more annoying and at what speed?

Robert Szczepansk (

I have had the BORLA for about 2 years. I live in NY and it has held up wonderfully. I would recommend it to anyone. Some people complain that it is noisy and what not. Ever hear the expression "If its too loud you're too old?" Anyway, the BORLA is very quiet at highway speeds(around 3-4K) The only downfall is maybe the price. I paid $250 2 years ago and I think it is more now.

Who makes a performance exhaust for the Infiniti G20?

Wayne Cox (

Stromung does. [Info and pricing are given above].

'Art' Arthur Kim (

Trust now offers the catback (stainless steel muffler / aluminized midpipe) BL-series for the G20. I have it. You can typically find it for around $475 - 505. Great power gains and it's quiet. Nice craftsmanship, bolts on perfectly. The kit includes both cat and muffler gaskets, three bolts (2 for the muffler / 1 for the midpipe hanger), and documentary in Japanese. After driving with it for several weeks, it has gotten a LITTLE louder. It doesn't come close to droning on the freeway and you can't even hear it at idle. Under full-throttle, you get a quiet, clean, low tone rumble.

A few negative things about it. The round (should of been oval for a better fit!) shiny muffler canister sits very low exposing the right hanger closest to the bumper. Watch out in the parking garages! The cheap looking 110mm megaphone tip is too far from the bumper cut-out!!! Probably the ugliest exhaust system I've ever seen! It'll let everybody behind you know that it's there. Oh well, at least the power gain is nice.

A comment about standard performance mufflers...

Merlin Johnson (

Between James and I, we have tried other mufflers (Flowmaster, Walker Dynomax, a generic turbo) and they all suck. They are too loud, "drone" on the freeway and are just obnoxious, I drive 50-80 miles a day to work and he drives about 120 miles, so we couldn't stand the cheaper mufflers after a few months.

What are mandrel bends in exhaust pipes and why does it matter if a pipe has them or not?

Merlin Johnson (

Mandrel is bent tubing that isnt crushed at the bends, it requires a special and very expensive pipe bender. It's kinda like pulling/flowing/extruding a pipe around a corner instead of kinking the pipe around a corner. Bend a garden hose to 90 deg angle and see what happens, mandrel bends dont kink or change size around a bend. [Editorial note:Mandrels are better because the exhaust gases flow smoother because the walls of the pipe are uniform throughout the whole length of the pipe. Pipe with kinks at the bends perturb and retard the flowing of exhaust gases.]

Is there any relieve to performance muffler noise?

See Matthew A. Trostel ( response in the Advice about aftermarker parts section of the FAQ.

As far as HP from aftermarket exhausts go, is it really possible to gain 15 hp from an exhaust system alone, with a 2.0L naturally aspirated motor? JW's told me that the POP Charger, computer and exhaust is good for about 18-22 hp, maybe a little more. Since the performance of the whole package is greater than the sum of the parts (being that all of the parts working together can net greater gains), wouldn't a 15 hp increase from the exhaust alone be a tad inflated?

Merlin Johnson (

You're right, HP numbers that high from a non-turbo motor are kinda iffy...but that's what Stillen claims, 15 from the Stillen and 9% from the Borla. I expect about 5 to 7 just from a muffler swap. I have talked to some people at the old Grimmer Philips, Stillen, and Jim Wolf and they have all said the stock muffler is very restrictive...but I would still tend to agree with you 15hp from just a muffer? Questionable.

What all the hub-bub about exhaust backpressure? I thought I read somewhere that backpressure is irrelevant and it doesn't matter how big an exhaust pipe you use and that bigger is better.

Sam Strano (

Not entirely correct. I agree that backpressure isn't relevant; the less the better. The hitch is that pipe sizing is very important to the flow of the system. The bigger the pipe is the less pressure is there, however if the pipe is too big for the amount of air an engine can move, you'll lose power, even though there isn't any backpressure. If you run a 3 inch system on the car, the velocity of the exhaust gases is going too slow down, because the gases have to expand to fill the pipe. And slowing down the exhaust obviously isn't what you want.

Merlin Johnson (

Check out my page: I've done some back pressure measurements using different systems.

I've been wondering about how much real-world contribution a performance exhaust system has on the performance of an SE-R that's been upgraded like mine ((JWT ECU, POP, HK$ exhaust). For all practical purposes, when racing a friends who have SE-Rs with fewer mods, there is NO clear-cut difference between our cars.

Merlin Johnson (

I have been telling you guys that it is only like 5-7hp with ANY exhaust on our car. Cat-back does nothing until you really step up in the mods. You do back to back tests in cars with or without an exhaust and you wont be able to make much headway, no single thing (besides a turbo or N20) is going to make your car a rocket. I have raced bone stock SE-Rs when I had the POP/ECU/Borla and I couldnt make any real headway until about 100mph.

Remember you are ONLY talking about 20hp with all those mods. I figure (from the amount of times I have been blown away) that for a car to blow away another car it needs like double its horsepower or torque. By blown away I mean it is really obvious the other car can stomp you at will. It goes both ways, we are able to keep up with much faster cars cuz we have a decent amount of HP, and not too many cars have 280hp, but we can't really blow away something, unless it is a 70-80hp car.

I hope that some of you guys are finally starting to see the light as far as HP, Claims, Mods, and how Reality works. ;)

Maintained by Ronald S. Chong (