2013 S5 coupes will have the supercharged V6 from the S4. They're a chip and pulley away from 350+ AWHP (check with APR, Stasis, Revo, etc.) and get high 20s for highway mileage, which is not too bad for a commuter car (at least compared to an M3).
None of this is to say they handle as well on a track, but I'm guessing an S5 would do just fine for freeway duty.
Audicare is like $800 and gets you close to the maintenance that's included with all BMWs (I think they consider things like brake rotors and pads to be wear items and not included, whereas they're included under the BMW plan...).