Before- AA Signature Exhaust, Cat-Back Only
After-AA Cat-Less X-Pipe and Software. The software has a launch control function that doesn't allow you to rev past 5K rpms, they will remove that this week.
It sounds amazing! It is a little more "Boomy" between 1500 and 2500, not question about it. I rode in a catless Dinan equiped car last week and, it is also more Boomy between 1500-2500 RPMs. It can't be avoided when you remove 4 cats from the car, I don't care what anyone else says about whatever system. I've had it on for 2 days, I went to Winn Dixie yesterday and a guy drove up behind me when I parked and said, "What the Hell did you do to the car to make it sound like that, sounds incredible!" He has an E46 M3 and couldn't believe the way the car sounds.