Before sourcing out for even wider tire, I would research & source out who has the stickiest car in the current market for the stock 295. You can go 325 all you want but if you can only find one tire manuf that makes an average tire that is somewhat sticky, you are still in the same position as before, which is all those power smoking the asphalt.
Originally Posted by LarThaL
Hardly overkill. If there is one real weakness in the M5, it is that it scrambles for traction with that much power going to only the rear wheels. 305, 315, even 325, if they can fit, would be a welcome change IMO.