Would recommend upgrading to a different barrel.
A adjustable tank.
Kick ass ROF. Very dependable. Once you get used to the trigger pull, very good with not chopping paint. Put a case through it when I first got it, and had 1 break due to short stroking the trigger, now that I've gotten used to it, I haven't had a break yet. I'm sure that the adjustable tank has something to do with that to seeing as it likes to run just under 800psi.
Weight, is about the only thing, but thats due to good craftsmanship of the gun considering that it made of stainless steal instead of aluminum.
Not to many after market upgrades for the gun.
Very good gun to go with. Would recommend to anyone looking for a well built reliable gun with a ROF comparable to electro's. And if you ever do decide you just HAVE to go electro it can be upgraded through AGD into an E-Mag!