I am looking to buy a set of staggered rims, 18 in, or possibly 19in . My question is how wide can I go on the back and the front. I know with the wheels I can go up to 8.5 in the front and 9.5 in the back but the tires are confusing me. I have heard ppl say 235 in the front and 275 in the back. Does anybody have any idea how wide of a tire I can go.

It would depned on the tire you choose, the offset of the wheels and the alignment setting on the car. To be safe it would be 225/40R18 and 245/35R18. You could go a little wider with the 255/35R18 on the rear but you may need to roll the fender lips.
If I can help let me know.

I dont think you want a 275 tire on the rear. your gonna need 400 horsepower to justify that. I think that would just make you understeer and slow your acceleration a ton

thanks guys I was asking because of an ebay auction that is ending today and I wanted to make a bid. I guess I will stick to 245 being the widest, however there have been some guys putting 255 on their sedans without rolling but like you said Jim I will play it safe utnil someone shows me that I can add 255 without rolling the fenders. If anyone has any other advice please keep posting as I will be reading a few times per day.