Looking to upgrade before you even have the gun or played with one is a rather bad idea. Get yourself a decent gun to start with and learn to use it properly. After a few games, you'll see the capabilities of the gun as well as realize its shortcomings, if any. Then you'll know what it needs in terms of upgrades. IMO, a decent quality stock gun is usually more than enough for any new players. Some people play for years without ever upgrading their guns and they have no issues at all.