Thought I'd give my impressions on the BMW performance exhaust that was installed on my 128 last week.
I had the performance air intake installed not too long ago. The exhaust completes a pretty nice package. Don't expect any neck-breaking increases in horsepower and torque. However, the car is definately more responsive. The engine seems to rev a bit more freely. Step on the gas while cruising at 2,000 rpms and you get a solid (but not neck-snapping) push in the back. The car is even more driveable and more fun now. I didn't purchase the intake and exhaust for the sound but let me tell you...it's incredible. I get a kick finding excuses to accelerate at every opportunity which doesn't do my gas mileage any good.
At low rpms you get a nice low growl. As the rpms increase the growl becomes higher pitched and tighter. Let off the gas slightly when you get to cruising speed and things quiet down. There is absolutely NO drone.
As for cost of the intake/exhaust package I did not pay MSRP as some others had done previously. I have to thank Dan at United BMW for this.
Here are some before and after pics plus a video for your viewing.
Video: