Updates or upgrades if you will are of personal preference. Its all opinionated. If you want more power there are parts you can switch in and out, which can boost the FPS of the BBs and give you tight grouping for shots at a distance. However upgrades are not easy to do when you dont have the knowledge of how a mechbox works. There are websites that can help you and guide you but its still a large task for someone whose never popped a box before.
Personally I believe the M4 or any aramalite for that matter is one of the most highly physically upgradeable aegs out there, lots of external acessories, lasers , lights, aim points, scopes, grips, and other do dads and bells and whistles you can slap on there with a railed interface.
Dont forget to order additional magazines for your gun.
I recommend these.
http://www.airsoftparts.ca/store2/in...roducts_id=879
Unfortunetly those are out of stock at that retailer at this time, however you can order mags from overseas as well. I still recommend the 68 round King arms. Their made of metal, fairly durable and feed well.
May want to consider another battery and maybe a charger for your gun as well if you dont already have them.
If you get a chance, please upload some pics for us.