New Rail For My G&G (Airsoft Noob)
 

I'm fairly new to airsoft and was wondering if this certain rail would work on my G&G CM16 M4A1 Carbine.
(5KU LW URX RAS)
http://shop.ehobbyasia.com/5ku-lw-ur...l#.Uy5-_qlDvcg
If it does fit, would I need extra tools/parts?

It would fit on the gun if you also get a new barrel assembly or modification to your current one. The reason is this, the front triangle sight on the CM16's is one piece with the barrel. The rail set you are looking at has a built in front sight not making them compatible out of the box.
If you have a dremel and are handy with it that wouldn't be much of an issue but if not you can take it to a local gun doc(fill out your location and we can better assist you) and they can do it. Or you can buy a new barrel assembly that allows you to change your sights/gas blocks.

Chop off everything above the red line as shown here;

http://i.imgur.com/dICPh82.jpg

It's an old school SOF type mod that was popular when mounting free floating RAS units before replacement gas block assemblies were commonplace. File all the edges smooth and touch up with some black bbq spray paint and it'll be looking boss.

I've already purchased a new barrel so I don't need to mod the stock barrel, and I'm planning on buying flip up iron sights.