The TRMotorsport wheels you're using I checked on at TireRack, and they show the 8.5 front but a 10 rear. So I looked at the E46 M3 fitment there, and that shows a 35mm 9.5" available. I assume you're using that rear wheel? Hence I can actually get these still from TR in 8.5/9.5 sizes. It looks like using a 15mm spacer will get the offsets just right (legal).
I was hoping to run the BFG Rival in 275/35 all around, but it won't be available until June. Yokohama doesn't make the AD08 in that size, so I've pondered running a staggered tire size. I was thinking 265/35 front and 295/30 rear, but that makes the fronts actually larger diameter than the rears (not sure what if any issues that might cause with ABS, etc, given the car is designed the other way around).
Anyway, that rear 9.5 they have listed under E46 M3 is the same wheel you're using?
2011.5 M3 sedan 6MT, Silverstone, no sunroof
2001 M5 LeMans Blue/Silverstone
2006 330i 6MT Red/black, ZSP, Nav, etc.
2001 Audi S4 6MT; 1996 Volvo 850R wagon