I'm going to buy the G&G combat machines. I want to do some upgrades but I'm on a budget. I know I could probably do all the research myself but I find it easier to ask other people who have already done it I know I want to add a new spring and hop up. But I'm wondering if I add a new motor would I need to get new gears and a new piston? Also if you know of any other budget upgrades that would boost performance please let me know. Thanks!