I read a couple of threads of members with Rancho and 33's and he said the tires looked too small. The Rancho lift really gives you about 5.5" of lift. I think 35's would be better. Another member has Rancho with BFG mud terrains on Factory XLT wheels and has had no problems, likes the look and the truck looks good.
This is ThumperMX113's lift with Rancho and 33's
and this is his lift with 35's
Really have to thank the members for their picks because they give everyone at least an idea of how our truck will look when you modify it. I hope THUMPERMX113 doesn't mind us using his pics.(Thanks) I'm still trying to find the other member with 35's on the factory wheel with a Rancho lift.