Will 245/45/18s fit on the stock rims for the MS6? I have a shot at a set of Blizzaks for $40 with 9/32 tread left....

I would say yes.

Looks like they might not. TireGuy on the 6club lists 245 40 R18, but not 45 R18. Must rub.

Intresting. That would mean the 8 has bigger wheel wells. They fit on 3's so I'd assume they fit the 6 to.

Maybe they will. Waiting on the TireGuy to e-mail me.

i ran 235/40/18 on my stock rims with no rubbing(just barely). Pretty sure 245/45 will be a problem, not with just rubbing but that is a wide tire to put on a 7in wide wheel. Just my 2 cents.......try this link it was helpful for me in sizing wheels for my car.
Tire/Wheel Sizer

Ooops my bad. 245/45. I read it as 225/45. That may be a prob. Don't ever listen to what I have to say.

I have 235/40r18's on mine and they are real close. I don't think they will fit.

245's will not fit on an MS6 under stock conditions for two main reasons:

1.) The stock setup of the MS6 wheel wells, without an enourmous fender roll that would be pushing the limits of the sheet metal.

2.) A 7" wide wheel, the tire is just too damn big. A 245mm wide tire is equal to 9.65 inches, those tires would be too far stretched to take any kind of corner, let alone a colorado pothole.

Kinda what I thought. Oh well. Thanks guys.