I am looking at them, what are the different kinds of 5100s? HD vs. non-HD? I have a 4" rancho on my truck, do i want the front w/ 2 in. lift or the front w/ 6 in. lift (i was thinking maybe my 4 plus 2?)
any help is awesome!

 

I haven't seen what kind of spacers the rancho uses, but you should be able to use the 5100's with 2" of lift. It will net you an inch or two of additional wheel travel too.
HD's are just heavy duty, they ride more rough.