I have had a set of those kumhos on my 2nd gen. They hooked up great in the snow for a mud terrain, but they seemed to wear rather quickly. I didn't have them very long, so don't really know how long they will last, but don't expect too many miles out of them.

 

My roommate has them on his *cough* Titan *cough*, and they have only lasted about 30k and are pretty bald. They aren't too noisy, and looked great for the first 20k miles!

 

Yeah, 33x12.50x20's should be alright. I just have a level on my truck and have more than enough room. Just wish they made a 35x12.50x20