Instead of going to 4 cells it might be better to restrict thr amount of turns to a maximum of ten and make longer heats: instead of 5 minutes there will be 8 minute heats which will be more competitiver so the guys and the back can also have a chance to get first. longer heats means better concentration and the chance is that even topdrivers like Hirosakaa and Hara will make mistakes in the last minutes so the others have a chance as well. Another rule could be adding some extra weight to the car if it has won a previous heat to slow it down. Just a thought.