Ditto to DRTYFN
I put 37" MTR's on stock rims as well, and have flexed the suspension pretty thoroughly off road (probably should say off pavement). With the suspension both aired up and down and no apparent rubbing.
Not nearly as easy to clean the wheel wells though
The only trouble I had was w/my local goodyear dealer....he wouldn't mount them without an O.K. from a goodyear rep....my guess is liability and/or warranty issues.