Scaling a stock suspension car.

If you are having to go to full throttle slowly, then that is why you don't have that much rise in the rear, or front.
Heims joint upper control arms and strut rod will loosen up the front end a lot! compared to the stock ones. Then i would install a urethane bushing in the lower control arm.
this will allow your front end to rise much quicker(with the same shock setting). planting the rear tire much quicker. This also would be a good time to add some /6 torsion bars while there out. if you don't have them already.

By adding weight to the rear end, might make you faster because you can get to full throttle quicker.

With my cheeter slick(old school bias ply tire with a tread compound slick recapped on it), by adding some weight in the trunk i pick up 3 tenths( this also was with some torsion bar staggering to make it leave straight.)

just some thoughts.