Thats a good point.... I wonder if it can be lowered and how low when on 19's. Some cars like the BRZ, once you put 19's on them, it already sits low enough. I think the tires would rub, so a little fender rolling along with a bit of negative camber might help them function properly without any issues.Fill the arches well
Don't think it could be lowered
That is true, if performance is someone's main objective, I'd say stick with OEM sizing or go slight bigger.Keep in mind the performance penalty you'll pay for having the larger wheels.
If you're upgrading the performance, then it might not be so noticeable.