If you are an Auto-crosser, SCCA released the classing for the Blackwings today.
CT4-V BW is BS (B Street)
CT5-V BW is AS (A Street)
BW5 competition in AS are things like: Corvette C6 and C7 (non-z06), Camaro ZL1, 718 Cayman, Supra, BMW M3 & M4 CS.
BW4 competition: Audi RS3, RS5, RS7, BMW M2...