Ok, so I have my G&P M4 just the way I want it for CQB; about 350 FPS at 24 bb/sec. It has a stock G&P inner barrel in it. I did replace the hop up bucking to an X High Tech Bucking. Overall it's pretty accurate for close range. Now that I have the CQB set-up, I want to get something with great range that I can use for outdoors games. I scouted out some spring and gas snipers and decided that they weren't really worth the money. That left me with an AEG. I figured that I might as well just get all the internal parts I would need for a DMR and just use my existing gearbox and body. Here's a list of my current internals: Classic Army High Speed Gears X High Tech 260% Spring SHS 15 Metal Half Teeth Piston Bravo Aluminum Cylinder Head Modify Piston Head (Polycarb) Modify Seal Nozzle Guarder Tappet AMP T5000L Torque Up Motor Echo 1 11.1V 25C Lipo I'm guessing I could keep the same spring since it should be able to shoot at about 450 fps (Which is where I'd like to keep it), but other than that I'm not sure what I should replace. Please give me actual part names/brands. Don't just say "get high torque gears"... I want reliability and durability out of my build, so keep that in mind. Thanks! Oh, I almost forgot. I have read a few places that V2 gearboxes won't hold up to the pressure of a very powerful spring. Is that something I should be worried about?