Just wondering if anyone can answer this for me.....Someone is selling 18" wheels with these specs and was wondering if anyone has had any issues on their NB 996: Front 18 x 9.5" 48mm offset; Rear 18 x 11" 52mm offset.
I have checked many sites and size recommendations are Front 8.5 and Rear 10.5.

 

I can tell you the rear width/offset on a 295 tire will barely fit under the wheelwell with copious amount of negative camber dialed in.

The front width/offset would not clear my Pss9 spring perch.

 

this page is your friend: http://www.1010tires.com/WheelOffsetCalculator.asp

You can go up to about 20-21mm of outer rim offset in the rear on a nb car I believe.
Front I'm not sure, but 9.5 sounds pretty wide.

 

I was afraid that those specs would be too wide. From the looks of the responses and the wheel offset calculator, I better stick to the recommended sizes.

 

you can go 18x11 in the rear but you'll need a wheel with the proper offset. I think the 996 GT3 wheels and some of the 997 wheels are 11", but have a 67 or 63 offset.

 

I have 11" rears with (295/30/18) with either 59 or 60 offset and they just fit flush. I have -2.0 rear camber.