Well, just got my APR/Borla cat-back exhaust installed today. Took it to a local Midas shop... installation cost $90 and took a little over an hour. When I first took it out for a spin, there was a terrible rattling sound which seemed to occur when easing off the gas pedal at high rpms... so I took it back to Midas and they found that it was caused by part of the exhaust bumping against a plastic-like block right around the center of the car. So they tried to tighten some stuff to bring the pipe as far away from the plastic-like block as possible... this seemed to eliminate the problem, although this evening, i noticed a slight rattling that lasted for a little bit... if the problem persists, the midas people mentioned they could try shaving the plastic thing a bit... doesn't sound too kosher, but it doesn't appear as if it'd affect the structural integrity of anything. Was wondering if anyone else has experienced this and if there's any way to completely eliminate it?

I haven't had a chance to get much time behind the wheel, but here are my initial impressions:
The exhaust sounds really sweet from outside the car. When they finished installing the exhaust, they started her up and revved it up a bit, and the sound really surprised me. Nice and deep... very sporty sounding... sent a small tingle down my spine when I first heard it! :) However, inside the car, the exhaust can kinda drone at times... when cruising around (70-80mph), there isn't much noticable increase in noise... but once you get on the gas at that speed, there's a pretty deep and loud drone. Can get kinda annoying, but I think I'll get used to it. In terms of performance, it does feel a bit faster and more responsive... of course, completely seat of the pants... I'm sure the nice, sporty growl adds to the effect! ;) Overall, I think it's a pretty good exhaust... if it weren't so loud when accelerating in 5th, I think it'd be great. Also, if I can completely eliminate that rattling that seems to occur very rarely, that'd make me feel a lot better too!

When I had a Scorpion System put on my 90Q, it took several trips to the installer, and involvement by myself to get it lined up properly. Earlier, when I just replaced the factory resonator, I went through the same thing. My conclusion is that installing an exhaust system is a study in perfect alignment and patience. Recently, when I had to replace a gasket, I had to start all over. It took several attempts to get everything lined up so that there were no rattles, leaks, or vibrations.

As for the tone, I found that my Scorpion system actually changed it's tone a little (or is it my imagination?) after being on the car a little while. The Scorpion was pretty loud under WOT, but there was no drone at highway speeds. Once everything is lined up and you get some miles on your new system, you may get less drone, or it may go away, based on my experience. So, get it lined up (you may need to help the Midas guy, if they'll let you) and give it time! :-)

Charles

I have the same exhaust *Borla* sme problem alignment is the key..My ehaust rattled by the rear crossmember really loud sometimes....What I did there is a hanger attached to the crossmember take it off and elongate the holes more so you can slide the bracket closer to the tire side to give more clearence in the middle because there is not much clearence there..and also the exhaust does expand when hot if you not the exhaust tips will stick out further after a daily commute, that also makes it a problem for rattling

I took it to a performance shop and paid $40 for install. After checking out the car after they put it on, I noticed near the center (underneath) it appeared as if (one of the 2)the connecting clamp bolt was unnecessarily sticking out. I inquired with the guy, and he explained the clamp must be installed like that due to there not being enough clearance from the clamp to the underbody. He could've mounted it so it would appear less obtrusive, but he said there'd be a good chance the clamp or assembly would rattle against the car. The lower part of the clamp is not an issue unless you get down on your knees and look underneath the car. Other than the clamp in the middle, he had no other mounting problems.

Maybe this is why you're getting the rattling, or they just did a lousy job?

I got the exhaust from AWE, but it's the same thing. It looks like they just grind out the inner tip. Works for me.

Anyway, There is little clearence with a big chunk of the drive train. It's a big aluminum cross member that gets in the way right in front of the resonator. The exhaust really needs to curve toward the driver side of the car further to the front.

I was able to add clamps to the hangers to keep the exhaust riding to the driver side of the car and this prevents the horrible rattling. However, the tips are not centered in the rear valence and have melted one side a little bit. I'm still working on getting it all perfect.

Another note. It rained tonight and the problem described by Andy Hedin and others is awful. When you run through pooled water it sounds like the pipes are resting on the frame. The drone is horrible and clunks and vibrates the whole car. Has anyone figured out a solution to this?

Other than these issues, the sound is fantastik. The turbo seems to spool quicker and has a much stronger whoosh sound. It also maintains 15 psi of boost, according to my VDO gauge, to almost 5500 rpm. Previously the boost started dropping at about 5100 rpm.

Good luck sorting the rattling.
Rich L.
99 1.8TAQMS, APR 1bar, K&N, Borla

I don't think it'll ever be an issue. The bright side is I don't have ANY of the issues mentioned, including by the post above mine. Forgot what the guy's name was... No rattling, or tips not centered....