Appropriate Wheel Offset for 18" Wheels?

Im not busting your balls here intentionally lol! Your mock up tire/wheel was a 275 tire yes, but on a 17x8. So your section measurements will not be over 10 wide I would bet. To end this debate here is what I would do: buy a pair of the fronts and mount the tires you want to run, then see what is needed in the rear with those. Prove me wrong!
This isn't fair. I want you to prove me wrong first. :violent1: :banghead:

Yeah, you're right... Section width was just a hair lengths wider than 10" so no 9.5" wide wheel. I was too into the numbers... So now my options are a 245/40/18 or a 255/35/18. Lame... :/

So the closest wheels to fitting straight off the market are going to be the Drag Wheels, again. At least their cheap.
http://www.summitracing.com/search/brand/drag-wheels/product-line/drag-wheels-dr-31-flat-black-wheels-with-red-stripe/wheel-bolt-pattern/5-x-4-1-2-in/wheel-diameter/18-in/wheel-width-in/9-000-in/primary-wheel-color/black?N=401891%2B349159%2B4294947558%2B4294920350%2B4294920748%2B4294920824&autoview=SKU

There's also the Enkei RP03 that comes in a +18mm and a +40mm (have to get the fronts together to make sure it fits) that may work. I'd just have to get it from a different vendor as Summit doesn't hold the +40mm offset.

http://www.enkei.com/rp03.shtml#
[ame]http://www.enkei.com/size_chart/RP03.pdf[/ame]