hi, the reason it doesn't fit is because the upper mount and where you adjust the dampening is designed differently then of the FLEX, which uses the EDFC.
Later this year, Tein is coming out with the FLEX system with EDFC for the NSX. Measurements are already done from the japan spec NSX, but they are waiting for the arrival for the Prototype, to test it out. (revalving, different spring rates..etc..)
take care
chris