Are Z-rated 235/45/17 usually always cheaper than 215/50/17 and 225/50/17? This will probably be the determining factor for me between 17x7 and 17x8 rims.

 

I don't know about, 215/50-17, but I know that 225/50-17s are only made by Michelin, Nitto, and like one other manufacturer. I would go 235/45-17, you can get Kuhmo Ecsta 712s for like 100 and and bunch of people here say that they are pretty good. Much bigger selection too.

 

You have the 17x7 5th Gen SE wheels, right? What size tires do you have?

 

Pirelli P7000SS, about $150 a tire, but I'm the idiot that got 225/45-17 instead of the 235/45-17. I read on Pirelli's web site later that they say that the 235/45-17 can go on a 7.0 to 8.5 rim. Oh well.

 

Well the 235-45-17 is a VERY common size. More common than the other sizes you mention I think. Therefore you will have alot of tire choices in this size and alot of price variation. I mean it can go from $100 each to $300 per tire. It's fortunate that Kuhmo came along w/ their Supra Esta 712 in the 235-45-17. I have then and they are absolutely the best value for $100-$108/tire there is. I am very happy with them regardless of the price. They only lack the ultimate grip that only the high end($200+) tires have.