Some thoughts on having installed a Full-Race Downpipe and Exhaust
When I first installed both of these (at the same time), the only other modification I had was a resonator delete and K&N drop-in. I threw a CEL within 25 miles. I thought I was going to need an O2 defouler. I also had horrible rasp at moderate to heavy acceleration. Keep in mind this was on the stock tune. After I got FlashPro, I uploaded the ReFlash map and the CEL went away. The rasp was still there, though. Fast forward a few months and I installed an RBC, ZDX, and 3.5" SRI. I also loaded a basemap calibration (tune) geared towards my mods. No CEL was thrown AND the rasp went away...COMPLETELY. I believe the car was just not getting enough air. Even with the ReFlash, which also runs rich. This was not an ideal tune at all.
Lesson learned: To run this downpipe and exhaust, you need a proper tune! If you do not get a proper tune, you may throw a CEL and/or have horrible rasp depending on what mods you have installed.
Thoughts on sound
This was ear-splitting loud when I first fired it up in my garage. It breaks in fairly quick, though. Probably 500 miles or so and its tone will become stable. It has a nice deep tone and the drone is nearly non-existent when just cruising. Nice aggressive sound during acceleration. After using a proper tune, it got even deeper and sounds better!