[Kozzie]

Doing a custom scratch build makes a lot of sense if you're experienced with airsoft but this being his first ever gun IMO it's poor advice. That being said don't buy a gun that you would plan on changing most of the parts as was previously stated it can be a waste of money. You may be best off finding something thats 90% you want stock from the manufacturer. This will be cheapest and easiest. Almost every company makes an AR (M4) and they come in hundreds, if not thousands of different colours and configurations to suit just about any taste you may have.

It's been my experience that a lot of players use their first gun for only a short time before they want something different or perhaps more suited for their discovered playing style. If you want a gun mostly for plinking just get a simple M4A1 configuration, there's no reason in spending money for rails and junk if you don't need. No shame in gaming one either. If you then get into playing a lot and discover you want something more, perhaps then it's time for that scratch build perfect AR, then this gun will make a great back-up/loaner/rental just in case.

ICS vs. KA: IMO KA is the better buy. I admittedly have no experience with one but I've heard too many bad stories about the split gearbox to ever want one myself. I generally try to stay away from proprietary parts in my guns as they can become issues when something breaks or you want to make an upgrade.