Answer:
RSX, if im not mistaken the RSX has the new spyder balance valve (slightly less kick and better efficiency) and a regulator, electra, while nice is nowhere near worth the price tag since the tech in it is the same as every other spyder. Also look into the EW-1 it is very close to the RSX and electra (its actually a rebadged vs1) selling for $50 right now, eyes and e-frame stock and can work off co2 (no reg or balance valve though)