I bought mine several years ago. Run it in closed bolt configuration. Cool to shoot, but kinda dwarfs the 16. The kits have gone through the roof now. Upper alone is about $1,500 if you can find one. The open bolt fire control kit alone is about $1,200. The magic green spring buffer setup is about $800. Talked to a fellow who worked at Colt. Went into a back part of the warehouse and saw them running over stacks of them with a loader to crush them. Said he almost cried. Tried to explain the value but nobody cared.
Sorry, don't know squat about Hi Powers.