The C5 has a fairly weak bottom end. You will have to be a clutch/pipe tuner to get some power on the bottom out of it. However it is more powerful than the WS7II in the midrange-top end rpms. Although it comes at the cost of fuel mileage. its a real powerhouse, almost too much power. Theres a reason why its not too popular of a motor with the team drivers. But its got BallZ!

Thats is a suspension problem. try taking some (if you have any) of the pre-load spacers out of the back shocks and put some in the front. Also try different mounting holes in the towers and arms. Maybe a different weight shock oil as well. it's all about experimenting with these things. ALTHOUGH, Jumpin speed bumps could be the reason it does that. Try jumping dirt/grass or something softer and see if it does it less. Plus if your landing with your throttle pegged on concrete, your asking for new pinions gears shortly.