yes, both spyder threaded

The Spyder pilot Acs is a Spyder pilot with an Anti-Chop System. It would be "better" than one without it because it is supposed to chop (when a ball is cut in half by the bolt before it has fully dropped) less paint.

RS, the electra may weigh a little less but is not worth the price difference considering the tech on the inside is the same

Nearly any spyder model will shoot the same as as the Bt omega. However it has a less durable design and will not look as "milsim" as the Omega was built for.

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)