Whether or not you rub with a 255 tire will depend completely on the specific geometry of the tire and how tapered in the sidewall-tread interface is. This is going to be different for almost every tire out there. The tolerances are just so tight. Even with my stock ZCP wheels and stock Conti tires, I only have about 5mm clearance on full lock.
Problem with then going to a 245 tire out front for the OP is that a 245/295 stagger is quite large.
After really going over all the possible combinations of everything a zillion times with looking at all the pros and cons, I have decided to stay with stock sized tires. I will just upgrade to Michelin PSS from my Conti 3.
Audi S6 * Audi S3 * Porsche Cayman GTS
--Former BMW M3 owner