My 2.0L Alfa had an 8 lb. FW--stock was nearly 19. WHile it was a bit more sensitive in response to throttle input, it had no effect on idle. You just had to play the clutch differently on launch, either at street speeds or under aggressive strip acceleration. Other machines with chopped FWs respond essentially the same.
I have to assume the Mazda be the same manner. BTW, when the clutch finally drops on my ride, I'm going the light FW route. The one thing I will do is have the clutch/ FW assembly balanced before install.