This spring kit is designed and developed in Australia by Crow Cams and is a direct replacement using the STD retainer. Heavier springs are required to run higher Boost. The installed height is 1.48″ , the installed pressure is 115 lb, the pressure @ .5 lift is 225 lb, max lift is .55″ , solid height is .90″ and uses std retainer and locks. 00026905