I have the ics cxp uk1 first AEG and a great little ish gun, light and grip fitted on first game!!!. Remember you'll need a few batteries, charger, extra mags possibly, speed loader if you have the low/mid cap, so you,ll need to factor that in, not a lot more but still extra....and possibly bits I've missed that others would recommend getting
Can you get to a shop?, I was looking at g&g but went for the ics after handling....got another I'm saving for now as well!!....although I'll need to pop back again for a feel
ics do a range of mags on fire support site, I have the 45rd and 180 rnd ones, boxes of 6