Question about springs....
For the springs though I need to figure out if I want:
1. TSP .660" Dual Spring Kit w/ Integrated One-Piece Seat & Seal, Titanium Retainers, PAC Springs #199-ISSPACPOL660 Spring Kit
OR
2. TSP .660" Dual Spring Kit w/ Two-Piece Seat & Seal, Titanium Retainers, PAC Springs #199-PACPOL660 Spring Kit
So I need to figure out which set of springs. But I also want to know why. Or what the major difference is between the two.
Thanks in advance,

