i'm curious 2 kno the difference in the kg/mm line of lowering springs.. looks like they have a couple different sets. on bulletproof automotive, they have a gold set, a lighter blue set, and a darker blue set, but only lists the DR Proceed R and the DR21 Proceed SS. and it also says these are replacement springs released as of 7/04. can anyone clarify the difference/specs for the kg/mm line, and any feedback in regards to the newer design? better? worse?