I would rate this kit as poor due the difficulty for young cub scouts. The molded wheel wells and air intakes are hollow (not solid), meaning you will have to perfectly cut out the back and glue them together for a filled in complete look like the picture portrays. This is impossible to get an exact fit with the weak plastic, and mine had several dimples. I ended up filling them up with fast curing epoxy, and using a dremel tool to sand down the excess. Then I fine sanded the pieces on a block to level them out. You need to be very careful with the wheel spacing. I installed an extra wheel and axel to make sure I had enough clearance before gluing the pieces. When you add the weight you also risk reducing the clearance between the cosmetic wells, and then you will have a very slow car if they rub at all.