I just got my 18' Gunmetal GT-C's installed on my sedan this morning.... it looks terrific! I used the S03PP 245/45/18 in front, with an 8' rim, and the 274/40/18 in back, on a 9" rim. The ride is a little firmer than before, and the sterring response and handling is remarkably improved.
I'll post some pics as soon as I can.

Cheers!

BTW, I'd be careful using anything wider than an 9" rim on the back of the sedan; the clearance on the 9" is fine, but a 10" might be trouble.

 

I love the GT-C's on the G35, esp. the gunmetal color you purchased - I'm excited to see some pics of your ride, enjoy them!

 

What offset are the front rims and what offset are the rear rims?

Could you please post pics showing closeups of the amount of clearance from the fender lip and clearance from the suspension control arm. 275mm width must be really close.

 

Wow! 275's on a sedan! Can't wait to see that!

Ivory Pearl/Premium/Xenon/

 

those are some big sidewalls.. You sure they are not 245/40R18 and 275/35R18


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03 G35C Prem/Nav/Performance/5AT
90 300ZX-TT HKS2835s and built motor.

 

There only 'big' in relation to someone using a 20 inch setup.... My reason for the 18"s is to keep a good ride quality, and give it a more aggressive appearance. I'm beyond the point where I need to get the biggest rim, and smallest tire profile I can.

BTW, the sidewall would be slightly smalller if I were using the 245/40 and 275/35.

Cheers!

 

The front offset is a +43, and the rear is a +42. When we test fitted the rims, I remember the suspension arm clearance depth to be about 1 - 1 1/2 inches, which is why I don't think anything wider than a 9" rim will safely fit the rear of the sedan.

The 275mm does come real close to the edge of the outer fender, but with these offsets, does not stick out beyond the edge of the wheelwell. I haven't tested it yet, but it looks like I still have a good deal of suspension travel available, without any rubbing of the inner fender lip on the tire. But, the 'rolled in' lip of the rear wheelwell is directly over the outside edge of the tire..... meaning that if you could possibly 'eat up' enough vertical suspension travel, that lip would eventually come into contact with the tire; which is impossible with the stock setup.

Hope this helps.