Right Sniper Stock for M16
The Right Sniper Stock for M16 Series might look fine, but is difficult to install properly. Since the stock is connected to the pistol grip, you have to insure that both pieces are aligned properly before tightening any screws -- that alone is a hassle.
Star Crane Stock and Battery
If I were you, I'd go for the Star Crane Stock and Battery. This stock is modern and has the ability to store a large battery in a collapsable stock. The 9.6V NiMH battery that's included is of high quality an can power up a 420fps gun. Plus at WGC, you can choose either a black or olive drab stock to fit your needs.
G&P Crane Stock and Battery
This Crane stock has a smaller profile than Star's version. The smaller profile resembles the actual real steel stock made by LMT. Because of the smaller size, the G&P stock can only hold AA celled battery packs. In my opinion, AA cells aren't the best for high powered applications. If you're aiming for a 350fps gun, then AA cells will do. The battery pack by G&P is also NiCD. This means you'll have to discharge it everytime you charge the battery. I would rather go for Star's NiMH battery to avoid the responsibility of discharging. The plus side about this stock is it's color availability. They come in black, olive drab, and desert tan.
FYI, the G&P and Star stock both have rugid build and can withstand punishment from a skirmish. The sniper stock is prone to spliting in the middle.