While not new to the AR world, I hadn't shot one since I sold my 16" HBAR Colt 5 years ago until this weekend when I shot my first DCM match.  What a blast!  Anyway, I now have the bug, and want to buy/built a DCM rifle.  As always, price is an issue, but I would hate to buy a standard A2 only to add a free float barrel, sights, new trigger, etc later on.  Unfortunately, my local DCM club doesn't have a junior shooting program, so the CMP subsidized Bushmaster is out.  What would you guys suggest? Should I buy a new DCM such as the Bushmaster, or should I build one?  If I should build one, what should I buy for components?  Thanks for the advise!

You really should ask this in the Competition forum....

How serious do you want to take this, and how good are you now? I have to ask because newbies usually aren't accurate enough to capitalize on all those fancy goodies.

A good quality off-the-shelf rifle with basic service class modifications (tube, trigger job, small rear aperture) would still be cheaper than a high-end build and can take you all the way in to Expert class, maybe into Master if the gods smile on your barrel.  Practice will get you a lot farther than expensive accessories.

Later on, as your skills appreciate, you can add on more and more stuff. (2-stage trigger, NM sight base, high-end match barrel, etc)

EDITED TO ADD:
If you start with an off-the-shelf rifle, be sure to get one with a 1:8 twist or faster unless you plan to stick with reduced courses only.