Nothing special, but I was trying to keep it simple. Got one of the Spikes and DTI kits from Cold Hand Arms. Added an Ergo Grip, Moe Handguard, NCStar fold down rear site, Aimpoint Micro dot clone (w/ riser) and CProducts mags, old school CAR15 stock. Never built an AR so this was very fun and easy. Props to Cold Hand Arms for such a good gun a a steal of a price. Upgrades I want include going to 11.5", little nicer backup site, BAD Lever, compensator (like on the FNScar but I cannot remember the name), Irene Sling.