Help me decide on tire/wheel size...
 

I'm on the fence between two different size options, and can't make up my mind so I'm hoping someone might be able to sway my opinion :D

The options are 17x8 with 225/45/17 or 17x9 with 245/40/17. The 8" setup is a bit lighter (assuming same wheels/tires), but within 1lb per corner of the 9" setup. Cost isn't a huge difference either, about $100 total with wheels and tires.

I know the lighter option will be a bit more agile/nimble, but is 1lb that noticeable? On the flip side, is the extra grip from the 245 going to be noticeable? Will that grip come at the expense of some feel?

The car is my daily driver, but will see lapping events and auto x in the summer. I'm not serious about competing, so something that is a fraction of a second per lap faster isn't as important as how it feels to drive.

If it matters at all, I'm looking at RPF1's for the wheels and Dunlop Z2's (pending reviews), Hankook RS3's or Kumho Ecsta XS'. They seem to be the best bang for buck tires.

If not as serious about it - then I would lean toward the 17x8 and lighter mentality. It doesn't hurt that the 225/45/17 is cheaper as well ($164 vs $184) plus the tires in the 225 size are available now.

I think the difference between 17x8 and 17x9 is not as much as the difference between Prius tires and sticky Dunlop Direzza ZII tires by a long shot.

I'm a fan of the wider set ups because they look so good, but if your wanting a lighter, cheaper set up and you're staying with the stock power levels then go 8".

What this guy says ^ I'd say Dunlop ZII 225. Tire rack has a review video on them already (seems promising but might be hype too) on 17x8.

If you want better feel as compared to "shaving tenth's" why not go with 215/45-17 and save an additional 2+ lbs... 215/45-17 Kumho XS or Hankook R-S3 on an 8" wide tire is a perfect fit and will give better responsiveness (Dunlops ZII are too heavy in comparison and will bring it back to stock-like unsprung weight). 225/45-17 are also larger diameter than stock...so slightly worse acceleration. The more than ~4lb a corner unsprung weight reduction of the 17x8, +35mm offset Kosei K4R's with 215/45-17 Kumho XS on my FR-S is a very noticeable difference from stock - smoother riding and more planted with much increased grip.

Putting 245s on the front is going to neuter the steering response/feel/turn in. But yes, more grip if doing autoX seriously.

I'm not even sure 225 is worth it on the front as some 215s are as wide in the real world.

I hadn't given much thought to a 215/45 on an 8" wheel, but it's definitely within spec and worth a look.

The 225/45's are the same diameter as my snows (205/50's), which really didn't effect much at all. The %age taller isn't enough to throw the speedo off compared to GPS at all.