Any chance anyone can tell me if 19x10.5 +18 all around will fit my 370Z sport Edition?

Rears will fit easy. Fronts, good luck with that. To make it VERY simple for most of those out there that haven't figured it out. To do a square set up, pick a set up that fits the FRONTS then use spacers on the rear. The fronts need a much higher offset then the rears so spacers on the rear is the easy part.

Biggest size I could run on the front for a 19x10 +22

It really depends on how low your car is and how much camber you want to run.

My set up 19x9.5+20 with 255/35 tires up front, stock height and camber.

http://i1109.photobucket.com/albums/...Z/S1035167.jpg

http://i1109.photobucket.com/albums/...Z/S1035175.jpg

I'm on swifts with no camber arms

Will I have any problems running a 255/40/19 on a 19x10 +22 in the front?

no

Thanks

Suggestions/Opinions
 

Here's my current set-up:

http://www.the370z.com/members/pfdax...tein-coils.jpg

OEM 19" Sport Rays

Front: 19x9 255/40-19 Michelin Pilot Sport PS2 with 20mm spacer (= +27), -1.5 camber
Rear: 19x10 285/35-19 Michelin Pilot Sport PS2 with 25mm spacer (= +5), -1.2 camber.
TEIN coils (mild drop)
SPC rear camber arms/toe bolts.

What I'm going with:

Front:19x9 +20
Rear:19x10.5 +25

My questions:

1) I already purchased a set of Michelin Pilot Sport PS2 305/30-19 for the rear. I'm thinking a 15 or 20mm spacer added?

2) What about fronts? I was thinking either 255/35-19 or 265/35-19? Getyourwheels.com stated to use the 255 because it would "look" better. I also don't think I'll need a spacer for the front?

Suggestions & opinions welcome :tiphat:
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Ok so I'm looking into some work gnosis gs2 in 19x9.5/11 what would be some offsets I could run to sit flush with no poke. I'm looking to run 305's in the rear and should be lowered on BC. The vendor is telling me I may need to roll fenders, does that seem right?

15mm spacer in the rear and at most a 5mm spacer up front but you may not need it at all. I would run a 255 just because it sits better on the 9" wheel then then 265.

:iagree:

Being 50mm smaller than the rear, wouldn't I experience some understeer?

You would probably get under steer even with a 265 but turn in response will be better with the 255 also. A 275 or 285 would be best to match with your 305 rears but the rim width is your limit. You COULD still fit a 275 on the front but then turn in response will decrease and it'll feel sloppy.