Started out as a pre-ban era Colt upper, HBAR 1/7 barrel, A2 FSB /no bayo lug.
New gas tube, gas tube roll pin
New front handguard retainer
New Bolt/Bolt Carrier
KAC RAS M5
Matech rear BUIS
AN/PEQ2 clone package (very nice)
Fixed A2 compensator
CAA forward grip.
1400$ with Surplus M68 CCO package
(Aimpoint Comp M2, QRP mount & riser and bikini covers)
ETA: the compensator was permanently attached by adco.