Slingdirt, Out of the box the car is setup for high top speed. You can get more bottom end by cutting about 3mm off the clutch spring and then bending a new loop and reattaching the spring. This will allow the engine to engage at a slightly higher R.P.M. This will give you a slight increase in bottom end power. If you want a big difference in bottom end CEN Racing also offers a Competition Drive Train kit which reduced the overall drive ratio of the drive train for more bottom end. This kit will reduce the top speed of the car slightly.