I agree with not wanting to spend much money on the rear exhaust, since it adds very little to no power. Even BMW claims no power, just a "more powerful sound" for its expensive exhaust upgrade. You can save some weight with a stainless steel aftermarket exhaust, and more weight with a titanium aftermarket rear exhaust, if that is important. And people do like aftermarket rear exhausts for the sound.
It is hard to say which has the best value when the issue is a subjective one such as sound rather than an objective one such as horsepower. Some people will pay a lot of money for the right sound -- there are plenty of $2k to $3k exhausts and in some cases that is $3k only if on sale.
The significant power gains come from removing one or both converters in the midpipe. That is where I am focusing my exhaust search. One cat, no cats, no resonators, one resonator, two resonators, etc., but it can interplay with the rear exhaust -- if you go with a no cat no resonator midpipe then you may not want a loud rear exhaust because the sound would be too much as some people have discovered after complaints from neighbors.
Last edited by pbonsalb; 10-21-2011 at 06:29 AM.