Exactly, same as I was thinking. If the game quality suffers because of slower computers, I'd say its a shame. Just do it, how 'heavy' are these physics? Can't you do it with a duo core?
Let's be honest, who still has P4 and that junk?
I just wanted to point out that the actual required cpu speed to run the new tire physics wasn't mentioned, so a discussion about raising the minimum specs is a bit weird if we don't even know whats needed
Just pointing out that it could be too much for todays highend cpu too (in theory, speculation!)