I am also interested in how loud will that Oreca system be especially because it is de-cat...Is group A louder than group N (i mean because of the diameter A-63, N-55)?
I am pretty sure that the group A is/would be louder.
Shame K-tec don't have the DB listed for them!
I quite fancy one of these to replace the stealth I currently have fitted, but don't want to run foul of tracks DB limits.