I have a moded Gauntlet in .22 and I'll share my experience with you.
Absolutely grab yourself a larger bottle. Something like this:
https://www.ebay.com/itm/3000-PSI-0-38L-Aluminum-Tank-Air-Cyclinder-Bottle-For-Paintball-PCP-5-8-18UNF/401411846052?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649 Get the tuning kit from jsairrifles.com (although I see it's gone up in price since I got mine... )
I had issues with getting the poppet to seat properly even after several burnishing attempts but the stock poppet works just fine after it was all said and done. So, maybe for the first step don't go all the way to the air valve and see what boost you get and venture further if you feel the need.
Threr's a plunger screw mod that can be done on the trigger to give you more of a two-stage feel that's easy as pie and cheap.
Adjusting the regulator is easy enough but you're gonna need some check valves and such which is gonna set you back anothetr $75 ish and a heck of a lot of pumping... save this for a rainy day.
Bottle, Turning kit (-poppet) & Trigger is what I would start with. Shoot with it a while and see if you want to go further. Haji (see vid above) has some great vids on most of these subjects. Watch them!
One note I will make is a pretty simple way I found to keep from scalping the o-rings on my air valve and bottle connector. I used a bakeable polymer clay found at a craft store to make two "lego" looking pieces that fit on either side of the air tube with the lego posts filling the screw holes. This allowed the o-rings to slide by with ease. I'll try to remember to post picts.
If you have any questions just shoot me a pm.
Hope this give you a little more insight and direction. Happy shooting!