Lernerville is one of the best dirt tracks in the game and also one of the toughest. When running the top, you want as little of slide as possible. The higher you enter, the faster you will be but the bigger the risk is. When running the top, try not to lift a lot on entry, as this may trigger a slide. The Driver set really helps to eliminate slide and works very well on both lanes. If you do plan on running the bottom, I suggest increasing the rear gear ratio, and stiffening up the RR of the car using the bump/rebound stiffness (up in bump, down in rebound)