Not really. Only have a tightbore barrel in it, enhanced hammer spring (only improves reliability in hot weather, not power), enhanced spring guide, metal mag catch and bigger O-ring to eliminate the inner barrel wobble. Only shoots I think around 300fps with 0.20g, maybe higher in hot weather (upgraded over the winter) but I also have a pretty much stock G19 and it shoots about the same too. All in the ability to try, nothing really in upgrades.
Saved my butt one day too a few games ago, I got ambushed by two guys about 40ft away from me, I did my usual "Matrix" thing onto my back, only hit on me was on my MP5, so I called gun hit, lying prone on my back and drew my G19, popped off a few shots at one guy through the brush, he got more bursts off at me but flew over me, I shot a few more and my 0.30g went through and hit him. He left to respawn, his buddy on the other side of the trail took off with him. I got out of there and used my G19 on my way to respawn to "get a new gun". Because I use heavier ammo, it cuts through brush better, and has longer range when needed. And, it hits harder so there is a better chance the guy will feel it and call hit.