Stock class rules uses oem springs, but these shocks have lots more rebound than ots Koni. These are revalved so both the front/rears match each other.
I have the football dyno somewhere but that tells you more of how they were built. True Choice, Pro Parts and Kons NA are the only certified places that work on Koni
AFAIK. You can always send them back to have a sleeve installed to make them to coil overs.