para saan? for performance? for drifting?
technically, there should be no performance benefit.

performance should come from the tires, brakes and suspension, not the wheels. the wider the tire, the better the grip. obviously, if you widen your tires, you loose response. this is the reason why it is very important to properly match the wheels and tires.

so stretching is done for cosmetics or probably on an economic basis (bili ka ng mas maliit na tire kaya mas mura). you stretch the tire and the sidewall is not parallel na to the wheel face. if you are on negative camber, it will allow you to use lower offset rims and wider wheels.

If you're stretching the tires the contact patch is smaller than it could be. More contact area = more grip in corners. i don't know how this can be applied sa drifting (no idea how it works). pero kung daily drive sya, not only would it compromise your handling, it will compromise your safety as well. mas madaling madamage ang tire pag ganun.

imho.