Get a +3 or 4. No true difference. They are both trailable. They will have some push to them, but if you drop the ass end some and adjust the camber and caster of the arms, that will alleviate most if not all the push. Your shock will have to be revalved for the + size swinger to have the full advantage of having it. My suggestion, if you are truely confident that you have 70hp and want an all around bike, go with the +3 swinger.