Dont buy a regular 2001 autococker and then trick it out, my friend did that and he got the benchmark and new pnuematics and a new barrel and he spent a ton of dough on upgrading his regular 2001 autococker. The STO parts work together well as a team. The Benchmark frame, beavertail, and Armson barrel round out the rather lightweight gun. I prefer this style of ball-detente better than the ball type. The powerfeed looks really weird on a 'Cocker, but doesn't do any worse than right feed.
Trigger is really smooth, if a bit long and heavy.
A lot of little things that I didn't expect. The gun had a feeding problem when I first got it, but turning the PF plug a bit fixed that. Barrel is loud. I run CO2 and have not had any problems with using it, but it's only so-so effecient. The safety was really loose-fitting in it's hole, and would sometimes engage when the gun was turned a little on it's side.