Just a few rips through the gears to test GoPro sound and see if there's a discernable difference between stock and SPORT mode when WOT (RS4 has a button that opens exhaust valves up from 0-1000 and 4000-8250 rpm in 1,2,3 gear and keeps the valves open from 0-8250 in gears 4-5-6. To be honest, the difference wasn't huge, but definitely a bit deeper sound in sport. The mic on the go pro got a little muted from the levels.