TM SOPMOD, prometheus internal bits (gears, spring guide, piston, piston head, cylinder head), eagle 6 spring, BTC Spectre MOSFET, firefly hop rubber and nub.
Put a decent battery (11.1v, high discharge rate) in that and it'll batter anything else you can get for the money, real sword guns included.
Depends entirely on the quality of the installation of course, if you just wedge the bits in without properly shimming, correcting AOE on the piston etc it'll be a bag of shit.