I was thinking the exact same thing as you. I'm looking on trinityairsoft.com for upgrades and i emailed their tech support and they said since the UTG is a clone, it should work with the maruzen upgrades, but they're not sure. Wow, that was one huge run on sentence. Yeah, I'm thinking of upgrading the spring to a 210 spring, new piston, ball bearing spring guide, and I would need a stainless steel sear. Just think, shooting aluminum .3 gram bb's with that sucker. If you do find good upgrades, message me.