Rockwells are not for you, they are VERY far from streetable in stock form.
A Chevy D60 and FF 14 bolt are the way to go for you, much easier and completely streetable and they'll hold up to 40's no problem if you swap the outers on the front to 35 spline.
This whole topic has been done a million times, you can search anywhere and find info on it.
Since you're not a member, search on google with: whateveryou'relookingfor site:coloradok5.com