So here's what I have so far on my upgrade list for the JG M4 Basic: 1. Systema Hop Up Bucking 2. Prometheus Precision Shim Set 3. ProWin M4 CNC Hop Up Chamber 4. Madbull Ver. 2 6.03 TBB (363mm, for M4) 5. Bravo Steel Spring Guide w/Ball Bearings for Version 2 GB 6. Magic Box 8mm Stainless Steel Ball Bearing Bushings 7. Bravo Silent Polycarb. Piston Head with Thrust Bearings 8. G&G Special Nylon Nano Co-Alloy Piston All I'm looking for is durability, RoF, range, and accuracy. Not much to be desired, right? One of the most challenging parts of this project is that I will not do any DIY modifications. I'm also pretty limited in the money department but I can always earn more. I have around $150 so far. If anyone sees something that should be corrected in the list, please let me know. I don't want to have to end up shipping something back. I also would like some part suggestions for my RoF part of the project.