Stretched on tires are good, the lower the profile, the more the stretch too by the way.
I have a 215/40/17 on a 7.5" rim and it's got a bit of stretch
Wide tires on skinny rims is shit because you get heaps of movement in the sidewall, and the tires don't sit flat against the road, with stretched on tires you get minimal sidewall movement which is best for performance, not to mention it looks really tough.