Grant, I didn't think the 20kg was to deal with power, i thought it was just for handling .
with the rear viscous i notice there's a slight lag time where it feels like 1 tire spins and then it locks up . mostly just when i'm in 1st gear around really tight corners, stand on the gas and initially the car just goes wide but then you can feel the rear lock up and the rear end will slide more. maybe that's Due to something else, but i'm certain that when you are in a tight corner you don't feel the throttle over-steer for a second or two ..
at the time the setup was OBX front torsen, Stock center, Viscous Rear (out of a WRX, but i believe all Subaru rear viscous diffs are the same?)
Additionally, playing with my STI (center on auto , Vs open Vs locked) i do notice that with the center locked , a bit of weight transfer (forward) and the car is very easy to flick into a drift and fairly easy to control that drift, that's what i was hoping to do to Betsy ..
Still i'm not sure if a 20kg center would get me where i want to be, fairly sure i can get one shipped for $800 though ... hmmmm
well i have lots of time, this is not gonna be a quick rebuild... hehehe
thinking about this more.. ya if i just switch from the viscous rear to a platted rear that lag time should go away right? hmmmf