Kid Red

I'm looking to get the BBS Ch 18s from TireRack.com but they recommend a 245x40x18. Every instance of a 8.5" wide wheel that I've seen has been matched with a 235x40x18 tire. Am I missing something? I don't want to order the tire package until I know if I should get the 235s and by pass tirerack.com's recommendation. Or will 245x40x18 fit without any rubbing issues and clear brake calipers, etc? I want to order these, but the tire size through me.

I have an 06 B7 A4 that I will lower on coilovers about 1 1/2" or so. I don't want any rubbing issues as this is my daily driver only.

Oh, and does anyone know if tirerack uses metal valve stems in their packages?

Thanks.