On the lighter exhaust you can move the center of gravity of the car up. That can be good or bad. For a drag car I would go lighter but if you want to the car to handle maybe. If you lower the car a lot you can move the center of gravity to below ground level and that is bad so lighter exhaust is better. But if the car wasn't lowered to scrap the ground you could be raising the center of gravity higher in the car and it will not handle as well. This just means you need to look at the hole package. This is food for thought.