ill just toss in
it looks like your looking to get the TM M16. Im sure you know already, but just incase, the TM armalites have incredibly bad barrel wobble and the plastic body doesnt last long. If your budget allows, I suggest going the route of a full metal G&P, CA, or ICS armalite. They may cost more then the TM, but its cheaper in the long run since sooner rather then later your going to need to get a metal reciever.
With CA, G&P and ICS armalites shipping with solid internals(metal bushings in all latest models), solid recievers and frontends that are solid as a rock...its a good investment.