limiting speed is a bit ott what makes boxes entertaining when they are is their sheer speed limiting it is one hard to enforce and 2 bad for the whole purpose of what Alan was talking about

people have said about lowering the weight limit for boxes,...tbh i think this would have to be drastic ie 7kg or less as its easy to build a box with little weight. however doing this does limit the motors etc you can use and the boxes will still remian and be even slower and boring