Wheel fitment question
 

Lots of folks go to F18 X 9.5 +15, RR 18 X 10.5 +15 for street use. 1000s of posts to read here, do a little search work!

Is there any particular reason behind running 17s?

^^^ What JHC said above (and what Heel is hinting at). Here's why...

No clue where those fitments are coming from but if you look carefully, as your widths go wider, so are your offsets, pushing the wheels that much further out. (Case in point: your hypothetical 17x9.5 -19 pushes the wheel out 2.5" (61mm). Clearance issues are highly probable. But if you have the room (you don't), no problem with that but while the offsets are aggressive, the wheel widths (and proper tire sizing to fit; being the more important part for true handling improvements) are pretty non-aggressive because you're limiting the tire sizes you can put underneath.

Your widest, 9.5" hypothetical wheel, is about the STARTING POINT for real rubber. You don't mention tire sizes and I'm going to say you're limiting your tire choices with "tiny" 17s. About the widest you're going to go on 17x9.5s before running into tire diameter issues is a 235/50-17, maybe a 245/45-17 but then, tire selection is limited.

As pointed out above, 18s are your best bet for proper fitment with "real" (that is, better selection of sizes and brands of) tires. Case in point: there are 7 performance tires in the 17" (245/45-17) cited. Conversely, there are 63 selections in 18" sizes. (Quick search for 245/45-17 and 255/40-18s on Tire Rack).

As mentioned, do more research in the Tire/Wheel section. Study pics and what others are running. You'll find that the suggestion above by jhc is about the most popular set up you're going to find. You can get more aggressive but figure on body mods (lip rolling at least) going more aggressive than +15 offsets, particularly where lowering.

If you're going to do a full set of wheels and tires, might as well start with a known working setup.

Ooooooo..... I get it now. I thought about that at one time - and would still love to run a banana wheel on my 33 - but I've NEVER seen a set of RS Watanabe in 5x114.3 (else I'd've probably bought 'em.). I think motiveJapan offers them custom drilled but not sure if they do a 4-5 bolt conversion. I ran across a set of F8Fs (also a Wat banana spoke wheel) in correct PCD and in 17s but they were only like 7" wide. Bought a set of RS-8s for one of my S30 projects - and sold them after I sold that car - and didn't want them for my current 99% original S30 project.

We're talkin' ultra light wheels here folks. My 15x8s were ~12#...

Would love to see a set of them on a 33 just for that throwback look!

Check it out, Mic! It's also in your favorite color ;)

https://cimg2.ibsrv.net/gimg/my350z....f868781d23.jpg

Assuming google translate hasn't mucked up the numbers, I believe the specs are 17 x 7 +30 with 225/50/17 up front and 235/50/17 in the rear, which is pretty conservative.

Ooooo, jumbo mudder rally car style!!

Ummm, thanks, D, but no thanks. If they were in the proper size, maybe. Guess I'll be sticking with my existing cache of rollers. Hahahahaha.