How are the 6 cells spaced.

I know there are 3 foam blocks that you can use to adjust the cars attitude in the air. If it is jumping nose down then space the battery back one block at a time. Just move the block from the rear to the front. Move one at a time and then go out and drive to see if it feels better.

As far as catching the rear end are you refering to something like the rear tires not getting over the peak of jumps and "casing" the jump. This refers to the back of the car landing where the transmishion case is insted of on the rear tires. The only help for this is to go off the jump faster to land further down on the downside of the jump.

Let me know if any if this helps or if I completly misinterpited the problum.