I'd look hard at midlength uppers instead of the carbine gas system. Nothing wrong with the latter but middies function real smooth.
Don't be in a rush to buy, definitely research and compare many uppers then choose the one for you. Same goes for every part you choose to put into your rifle.
BCM has some extremely high quality uppers in 16" and 14.5" for about $385 without BCG, charging handle and hand guards. They also have blemished complete lowers for $270. A lot of people go with blemished since you save about $90 for a few cosmetic issues that you'll end up doing yourself in a short time to a pristine one. Worth spending some time on their site. A Spikes lower would be fine but there are some recent links here to a $59 stripped lower that would be just as good.
The standard milspec trigger is fine and probably more reliable so no need for a two stage trigger unless you've compared and like it better. This is one area that's clearly up to you, no need to apologize for choosing what you like.
Last edited by Quentin; 08-08-2010 at 04:11 PM.