spring block things, for drag racing Options

[celicaracer18]

i read in a magazine a while back that for fwd cars an easy mody that will help really good for traction is to but something in the rear springs that keeps them from compressing the whole way, and hence gives you better traction.
what would be good to use for this do they make something specific, who would it hold in place, where could i get them. answers to any of these questions would be nice

[playr158]

what you could do is, measure the stock compression distance...between the top and bottom of the rear shock
then temporarally make like poles to that length then mount them in a circle on a bracket that would fit inside the springs?!?!

but never heard of what your talking about