Some folks build in the jack screws to the 2+2. Just like some have flaps and some don't. Doesn't the PA14 have a higher AOI than the PA12?
http://www.supercub.org/forum/showthread.php?35282-Wag-aero-2-2-rigging
I would hope that a 2+2 if kept light as possable would have similar performance to the PA18???? I think maybe a little better cruise too, Haven't figured that one out yet.