[LotusBoy]

Hi Tom, hi OZ ! A friend of mine, let's call him "R", runs PSS's on his 1M, front and rears. He's one size more than stock: 255/35/19 and 275/35/19. No rubbing at the rear ! No issues at all, just more grip.
But... I wouldn't recommend increasing the aft size much more, if you don't increase the front size as well.
Let us imagine you put 245/35 in front and 295/30 aft. Aft grip is increased, so you get better traction when accelerating. Forward grip is not increased, so you get understeer the rest of the time, altering the balance of the car...
So I think it's nice for the looks, but bad for the driving !!