If you want a match-grade rifle, I recommend *NOT* building it yourself. While you may think that piecing it together from a stripped lower might work out, chances are it won't. Also, you might have to get quite a lot of tools. You are FAR better off buying a match rifle in one piece, which may or may not have a matched upper/lower and checks done on barrel headspacing and etc. There are a lot of companies which make excellent match rifles that have impeccable accuracy and will not break the bank. Rock River, for instance, makes extremely accurate rifles which you can configure on their website and from the factory will give you easy 1" groups @ 100 yards. DPMS also makes very accurate match rifles. Both these companies have very nice prices based on the quality of their products, and they are fast to support/fix issues (not that I've had any with either brand). If that isn't cool enough and you want all the "big name" parts, you can buy from Daniels Defense or those places to get the whiz-bang barrels, but its all gimmick. Most of these companies use parts from the SAME places. For instance, Remington uses DPMS for their ARs, who uses barrels from Wilson and other places. Rock River uses Wilson barrels for their match stuff. So why pay for a name-brand rifle like DD or Noveske when its all marketing? It does NOT make them any more accurate. And that whole "Milspec" deal is the opposite of what you want in a match rifle, since you want a super tight gun held to higher standards.
I see people making "custom" ARs from stripped lowers with all this high end stuff on it... They spend A TON more, spend more time, usually ding something up, have weird quirks (and no company to send it to for free fix, since its their own build), and it usually is not any more accurate than an off-the-shelf rifle from any manufacturer. And the resale value of a customer build is a fraction of what the cost of the build was, and a fraction of what the resale value of an unmodified commercially purchased complete AR. No one really wants to buy a home-brew rifle from someone else if they don't actually know you.
I've built ARs before, but I realized their resale value was terrible, and that professional places do a far better job for far cheaper than I can do. My RockRiver with heavy match barrel easily is as good (but usually better) than custom ARs I see, or of big name brands like HK or Noveske (in particular I have seen HKs with horrific accuracy at 100 yards). Those people yell mil-spec till blue in the face, but it sure doesn't help them put holes in the target at the spot they want them.