The Quadzilla ZXT and Xillerader boxes are also fuel only boxes. Carefull though, their new ZXT+ adds timing too. They are working on a new race box for the 24v's though called the Adrenalin. A lot of guys over on DTR are beta testing it right now. Seems to fuel as hard a tst/smarty stack on the bottom end, but keeps on fueling in the top end too.