Out of those, only an ASA and a barrel are the only upgrades you'll see results with. An on/off ASA will allow you to stop the flow of air from your air tank, making screwing the bottle in/out much easier. I put a un1tech on my slg over the diddy little stock proto barrel and have never looked back. Un1tech's are fantastic barrels.pointless (aka "i-got-cash-to-burn") upgrades (for a SLG UL):-
- change Proto Hyper 3 reg for DM series Hyper 3 couterpart cos it looks nicer
- fit a DYE NT airport in lieu of stock ASA
- virtue grips
- virtue laser eyes
- virtue board
- better barrel (DYE CF boomstick; overkill)
i'm guilty of the first 3 listed above and the last one but came to my senses and let go of the CF boomstick for standard DYE UL barrel(s). The NT airport is pretty handy actually; i'd recommend that you get yourself an on/off ASA.