tread has to be withint a certian range to not cause damage...a few solutions to this...
buy 4 tires
shave new tire down to same tread as other 3
AEM CAI, X02 fmic, MR header with intergrated UP. Invidia Catless DP, MR Quad Tip, Cobb AP...Traded in for an A3 S-line I miss the leggy tho!