"Seeing as the "custom" package does not include internal upgrades, you, the potential buyer, should know that the gun has plastic bushings, and a plastic spring guide, as opposed to metal. Recently I upgraded these internals, and depending on where you buy it you can get a good guide spring for about $15-$20 and a bushing set for roughly the same price. I will note that this gun has a version three gearbox with 7mm bushings. It is a decent gun that after about a year and a half, the spring decompressed to shooting an even 300fps. My internal upgrades also included a spring upgrades so it now smoothly shoots about 400fps. This is a good gun overall, but even though it says "full metal" this is only the case for the gears. With a complete upgrade of internals you can feel comfortable running a 9.6v battery off it with no problem, though i would not recommend this until you have made the upgrade. It comes with a plastic pistol grip, a plastic stock, as well as hand guard. I have personally replaced the handguard with a quad metal rail system, which significantly increases the weight of the gun. In regards to the stock, it comes with two very short screws that in my case have stripped, causing the stock to come off. At this point in time, even after installing new screws, the stock is very wobbly and cheap. I looked into getting a different one, but the receiver on this gun is very unusual and there are no generic stocks out there that i have found that will fit the gun. The magazine that comes with the gun is very cheap plastic that came broken in the box. I was however able to fix it by pulling it apart and adjusting the internals. The gun itself is fine, but if you are looking for something that will last you a long time I don't recommend you get this one, unless you are willing to drop more money on parts."