So I went to a how today. The cars that are in the 150-160 range are made from Solid layes of advantex. 4-5 layers thick. The 155 car runs 2 subs and has 5 sheets of advantex and 2 sheets of ply as well. Also he runs 4-5 MA 4000 at 16 volts. The 160 car is the same set up with 12 batteries... Google team renots to check them out.