Having a hard time. I lowered my mustang with progress springs. Since doing this is I now have all kinds of banging now noise in rear. I did not change the shocks. I now am not sure what I will do. Put the original springs back and have the car riding high but no noise'. Are there lowering springs out there that do not have these problems I also have seen that there is a difference between coup's and convert,s not to mention the cost of all of this.. Any thought s or suggestions will be greatly appreciated. Thanks Aidenshep....