It all depends on the pulse signal from the tach as to how it mates up. And, besides that, Dakota Digital makes signal translators that do that for you anyway if it isnt the same. v8 guys use the DD stuff for the Speedos and they work fine. All you have to do is calibrate it. This would be alot easier if you could just massage the whole RX8 dash into the FD as otherwise it would take alot of work and money to do a custom fit solution. That and you couldnt really do a kit for it as each FD dash would have to be modified heavily for it.