I was thinking of doing this:
18x8 = 245/40/R18
18x10 = 275/40/R18

Will this make the front tire look "beefier", ie. more sidewall height, than the rears? I don't want the tires to look awkward on the wheel. Should I go with 35's in the front instead? Thanks guys.

 

245/40-18 looks and works perfect on the front. (thats what i'm running now.)

 

No, front will be lower profile than the rear(less sidewall height).And yes, this is good fit for 18x8.
I do not know about rears...