Can't say I've thought about an A7 (more of an Avant guy, so the A6 as need somewhere to throw the dog - A7 looks very nice though), but that engine is AWESOME!! Definitely the biggest thing I miss about the SQ5 - 40mpg is definitely achievable on a run, and the torque is addictive, and while the sound is fake, it is at least in the exhausts so the same inside and out (and realistic enough that most people don't believe you when you say it's a derv).
Only downside is the wading depth is only up to the sills due to the fancy exhaust (and possibly a low slung turbo they don't want getting cracked if submerged in cold water when hot) so not so good when it really rains!
I didn't get round to tuning mine, mainly as I didn't feel a great need, I can only imagine at stage 1 400bhp/800Nm it's MENTAL!
Enjoy it! Looking forward to pics 
Audi RS3 Panther Black with all the options expect the Pano Roof

VCDS Genuine Rosstech USB-HEX+CAN Owner - PM if you want any coding/mods done in Dorset in exchange for beer/money