We raced an IROC typr race here at the Dungeon for several years, the cars were Parma flexi 2 with 16-d motors, the controners were Parma 4 ohm and they stayed hooked up, the cars were colored to the lane and stayed on the lane, at the end of the heat your spot was marked with a lane marker, all cars were taken to a table then you picked up the next car you would be driving and placed it at your lame marker.
One month we might race with a GTP body and the next race it might be a Jupter Thingy, or Manta Ray, Lotus 40 to name a few.
The problem was up keep on the cars, plus most racers wanted to race there own cars and controllers , so we stopped this class.