I sold my Remington R-15 a while ago (I just decided I wanted a black AR rather than a camo one) and finished putting together another one that is what I originally wanted.
Stag 5.56 lower
Timiney 4# trigger
Sabre Defence 18 inch Stainless fluted 5.56 1 in 8 twist barrel
Jojo's muzzle brake (pinned & welded
YHM Diamond pattern 12 inch hand guard
aimpoint M2 sight
Primary Arms 5X magnifier
Rail covers by Troy Industries
I bought the complete lower from a local dealer and replaced the stock trigger assembly with the Timiney one peice unit. The upper was purchased complete off the internet from PK Firearms. It came with a Vortex flash hider which was removed and replaced with a muzzle brake by Jojo's gun shop to satisfy NY state law.
The rifle is very accurate and I've had it out once and put 150 rounds down range a few weeks ago.