hi there
teh asso rc8b3/rc8e /rc8t/rc8/sc8..thunder tiger st-1 center diff is a direct fit without any modifikations to the mugen diff
i drive it by my self. the plastic spur gear of asso is soooo durable, you dont need here spare..
the driving is wonderfull, it seems, the car is lighter when you see it driving without that ugly metal spur noise
mihael