I've got a set of stock wheels with 235 MTR's wrapped around them, and I thought that was pretty good. I looked into, and bought, a set of 1" wheel spacers that certainly gave my Tracker a better stance. I also noticed a bit more stability on the highway and in the snow and so forth.
My only concern is the tire rub at right turn lock, (not left for some reason) and the steering problems that might occur from widening the wheelbase. This makes sense since now the inner wheel turns tighter and the outer wheel doesn't turn enough. Don't know if anyone has had this issue and I haven't noticed anything significant but the physics are there. Probably just might need an alignment if it becomes an issue.