Hi all, i basically have no experience with AEG's (so please excuse any mistakes ) and was hoping to pick something up relatively cheaply and get a few upgrades like hop rubber, stronger spring etc to make it more decent/skirmishable, but was wandering if this gun actually is upgradeable? http://www.airsoftworld.net/classic-army-airsoftrifle-aeg-m15a4-carbine-transparent.html im not wanting to fork out on upgrades unless they really will make a difference. I most concerned on improving the range which i expect can be done by getting a new hop up rubber ( if not then please correct me ) and changing the spring to raise fps but are there any other nessesary upgrades that would need to be done to accomadate a new spring? ie. in spring guns you often need re-inforced sears, do you need a better gearbox for AEG's? any other info on reccomend guns/upgrades etc. would be much appreciated. thanks in advance, Rex.