I have the hypertech max energy on my 99 and it really complements my mods - banks header, 60mm bored tb, intake, full 2.5 exhaust with flow and magna hi flow cat, and more... really as a stand alone it does not do much - i really felt a little more top end and all the shift point stuff felt firmer... the max energy model is much better in my opinion that any other programmer out there... this version superceeds the older programmer and is the best programmer out there - better than jet or edge.
cool features of max energy: obd reader, multiple modes for fuel
bad: price, xj model does not support all feutures