I think the 2.5 is way too much for that car. A friend has one, and when he's running at a good speed, then hits full throttle, it will still wheelie and flip on it's back. It gets too much air underneath when it's running fast. He even put lead 1:1 wheel weights on the front, but it still needed more. To avoid dead weight, move your battery pack as far forward as you can. You might also want to change your shock setup after doing that.