Will 17x10.5 fit my setup?

Depending on how the magnapacks catback is setup relative to stock it shouldn't rub. It may or may not rub on your quadshocks, just flip them if they do rub. And go ahead and run a 275/40 tire up front, it will look better and you will have more protection against the curb. As far as tracking goes i noticed my steering was a little more sensitive when mine were first put on. But i just took a 600 mile trip and the car tracked great, it went straight quite a ways with my hands off the steering wheel.

I have the same setup and it fits perfectly and looks great..go for it. (I didn't have to mod anything either)