couldn't agree more, eper. Nothing jumps or lands like the RB6. It sounds to me that maybe the jump isn't built right, or the car is seriously tweaked (usually a bound shock or suspension arm).
Take a video of your car going off that jump, and post it up.
The only thing setup wise you have posted that might be it... is if using the stock pistons, your rear oil might be a tad light? If the jump isn't stellar, and your damping is light, you might be bottoming out or something on the way up? hard to say. video would sure make it easy