Found a really good deal on some XD Series Ambush 18x9 rims and either 325/65/18 Nitto Terra Grapplers or some 305/70/18 Nitto Dura Grapplers. Right now I've got the factory 20s and some 285/65/20 BFG ATs. Any one have any experience either going up or going down in these rim sizes? What can I expect...better ride and handling with the 18s? Never had aftermarket wheels before.