I was under the impression that the HJ/Att produced more power than just the J/A. I spoke with someone at Edge today and they said that as long as you have the Attitude monitor it allows you to access level 5 for a 120hp setting, ("the same as the HJ" according to him.) I thought that the HJ changed the 5th level, but I don't really know. Also, has anybody tried the HJ w/ and w/o the Att. to see if it makes a difference.