It would make sense slotting it smack dab in the middle of the RS5 and R8. What they need to do is bump up the base R8's 4.2 with either more displacement or FI. Give it about 480bhp so the Qattro has some breathing room.
Past:'08 E92 335i|ZPP|ZSP|6AT|four (4) HPFPs
Present:'15 Mustang GT|401A|PP|6MT|Recaros
Sig pic unrelated. I like to go sideways and stuff.