What is the cheapest way to fix bouncing problem? Replace rear springs with revised one and redo rear alignment? thx.

 

Since the revised rear springs have a heady 24% increase in rate, your already taxed oem shocks will see the problem worsen exponentially. Do not source the problem to the springs, it is the shocks job to control what the springs are doing. Replace the shocks with revised shocks or Tokico D-spec shocks. You should be able to find the shocks used in the $200 range, D-specs in the $500 range new.