Start up quietness, to work with the OEM system versus being "on" at all times and I currently have a catted AA downpipe. I just wish I had the option be quiet or quieter when I need it to be.
Audi 5000
99 BMW 323
03 350Z
04 SRT-4
03 EVO 8
06 GTI
07 STI
08 EVO X
11 WRX
13 FOCUS ST
15 WRX
08 BMW 135i
15 Mustang EcoBoost
15 Mustang GT
17 STI
14 BMW 435xi
17 Focus RS
17 BMW M2
20 Supra
You can say I am a huge fan or cars :)
I wish this came with valves to work with the OEM functions, it's my fav sounding and looking exhaust out there (owned 2 exhaust as well and love the company)