[Nine Ball]

Personally, I'd never run a 315 on anything narrower than a 10.5 wheel. That pic above of LTDodge's old wheels definitely has sidewall bulge, since the INVO usually has a perfectly flat sidewall when installed on the proper width wheel. In fact, your car actually will handle better when using a slightly wider wheel, resulting in a slightly stretched sidewall.

Will bulge hurt? Not if you aren't competing in road racing or autocross, or doing death defying high speed curves on the highway. For the majority people who just commute and burn a little rubber from stoplight to stoplight, no biggie.

I'm a bigger wheel/tire fitment critic than most people, but in the end it is really up to what you find acceptable or not. At least if you buy some 315 tires, they will be easy to sell if they don't fit to your liking.