Do I have to modify to fit 17x11s
 

I just ordered my tires for my new zr1s and I will be putting them on in the next week or two. Do I have to modify anything to fit 17x9.5 up front and 11s in the rear?

Unfortunately, that's not a simple answer. The best answer is...probably. But maybe not. Or absolutely.

Didn't see any info on your car, so I'll assume you have a 'Maro, and not a 'Bird. The 'Maros apparently have a slightly smaller rear wheel well, so you may have to 'massage' the inner wheel well with a hammer. You might also have to roll or cut the fender lip.
If you're lowered, you probably at least need an adjustable panhard rod to get the rear properly centered.
You'll probably also have to remove or modify the "jounce spacers" - they tend to sit inside the rim, and can prevent you from jacking up one side of the car at a time - I get around this by always jacking up the entire rear rather than trying to do one side at a time...
good luck,
Shane

Yeah I have a Camaro. I guess Ill have to see when time comes. If anyone had to modify let me know. Travis

My car is LOW and all I did was use an Adjustable panhard rod. I have only hit the lip of the fenders once and that was because I was seeing if they would do it. ( I basically had to swing the car from one side to the other) But that could be because of my spring rates are pretty high.
My tires do not rub on the inside of the wheel well like I thought they would. (My 16" stock tires rubbed the inside of the wheel well. I guess it was the warn bushings in the stock PHR)

In addtion to not mentioning what kind of car, you also didn't mention which offsets you got for the wheels. The offset will play a large part in what you might need to do to make them fit.

I got the right offsets 50 and 56. AFS are wonderful to work with. They sent the wrong ones first. Picked up the shippment and sent the new ones which should get here with my tires at the same time.
I just want to be ready when they get here if I have to modify a little or just put them on. I try to plan everything out.