I'm looking to put 19x8.5s in the front and 19x9.5s in the rear and want to know what tire size I could fit on the fronts and rears.

My guess is Falken GRB 245/40zr19s for the front and Falken GRB 285/35zr19 for the rears.

Kurt Busch is the Champion!
 

17x9 is common in the front as is 17x10.5 in the rear.

Yes, but I'm getting 19s so if anyone could help out with tire sizes, that'd be great.

AC white face?
 

it's onna be hard to find 8.5s for the front and 9.5s for the rear...

jsut get a 9" front and a 10.5 rear?

This tool works wonders:

http://www.miata.net/garage/tirecalc.html

I've found the rims, I need tires that aren't going to rub.

Camber Issues
 

Use the calculator.

I did and the tires I like are "exactly" an inch larger. I'll go ahead and start saving for my tires, seeing as they're $203 a piece for the fronts and $320 a piece for the rears.

and u're also screwed when it comes to rotating them....so long tires...

I would get the same size wheel/tire all around so you can rotate them. But it's up to you.

also in wet weather u're rear end is going to wanna fishtail like crazy...

285 on a stang, will rub fo sho, i just say get some 18" deep dish bullitts, and you can run the 285, cause of the backspacing...

you need space back there for a 285, or else its gonna rub that exhaust i believe

You can run 315's on the rear with no rubbing. Mustangs handle best with 275's all the way around, I think that is the setup you'll find on most autocrossers. They don't need any more help understeering, they do a good job of that already.

A word of advice; set some money aside because the first time you hit a curb or a good pothole with those 19s you will be buying a new tire and repairing a rim.

Don't worry about going staggered. Z rated tires don't really last long enough to matter if you rotate or not. Keep your alignment in check and you'll be all good.