Scaling a stock suspension car.

Yes ^^^^^ the rear sprAng department can also help here. The SS sprAngs are designed to eliminate this. What rear sprAngs do you have now? Of course getting the weights correct at each corner will only help even more. I'd like to know which scales you got. Can you show us?

I bought the cheapest proform wired ones, from jegs with there discount it was around 750. Rear leaf springs are homoligation of a couple different ones, could definitely be part of the problem.