Got rid of those junk clutches a while ago... I'm sure the new versions are better but I had two motors throw bearings due to breakage on the old elektri clutches. Tossed them all and I will be staying w/ the long shank pinions thank you :)
I use an 8ight e plastic spur on my brushless muggy. I had to put two spacers in the center diff mount to keep the spur from rubbing but it works great!