The car seems awefully stiff. Like RC Old man says, try a lighter spring, BTW, the reds are lighter then the Yellow,
I think from the top of my head...
Black = 6lbs
Grey = 10lbs
Blue = 15lbs
Red = 20lbs
Yellow = 25lbs ?
The best setups I ever drove with the old car were with blues or reds depending... Start with the blues all around, and go from there.
Also check your droop, my car liked little droop in the rear < off power