What's the bigger impact:wheel/tire width or tire compound?
 

I ask this because I can't seem to find a rim that like. With the car now up to 517+whp I think I should go wider. Currently I'm on LMGT4 8.5"F,9.5"R and I love the rims but I want to go either up to a 19" wheel or stay 18" with a 10.5 or even 11 in the rear. If I don't find what I want, exactly how much performance am I missing out on if just keep what I've have and throw stickier tires on or should I just keep searching for a wider set of rims that I like?

Here's the thing, the widest you should go is probably 9front 10 rear. Otherwise your getting bigger rims for no reason. You can fit a 305/30 on the back of a 9.5 so getting a 10.5 cant benefit you as any wider and your almost certain to rub. So, by getting a 10 you are adding .5" of insurance that your tire will fit perfectly. Getting larger than 10" and you push your rim out further aiding in the tire rubbing, more weight, and useless width on a wheel that you can't fit wider tires on. Know what I mean.

Hell yeah!!

Impact on what? Straight line acceleration?

Overall performance. Straight and twisty stuff. I rarely drag race so straight line is second.

Then I will say sticky tires. I’m trying to think of a place on the track (street) where you accelerate and need sticky tires. Coming out of a turn is about the only place. Whether you have 230 hp or 500hp at the wheels, acceleration still must be measured. Some I'm going to say tire compound not width.