Just save the $$$ for a real clutch diff bill, if u get either rear wheel even slightly airborne then it goes open diff style... plus they tend to break a lot..

Back when I used to race a 240Z with a VG30ET in it at sebring, we would break the quafie every 10 hours tracktime.. we then went to a nismo and didnt like its lock up qualities, but the KAZZ seemed to fix all our problems for relibility and handling