Many of you have noticed that CT has discontinued the 4.55. There have been a number of well-documented 4.55 failures in boosted applications. The physics are simple, the 4.55 has more teeth (the teeth are skinny) in the same circumference of the ring gear, and is not as robust as the stock 4.06 (the teeth are fatter). If you have a 4.55 and a boosted application, one choice is to tear down NOW, before it fails, and you can sell off the gear. Since it's been discontinued, they are holding value for the street crowd. They aren't going to stand up to the rigors of track use.
Len, don't hold your breath on it 'not being too bad'. Mine was still running under it's own power, several teeth had broken off, but the ring was still intact, so the car would still go, albeit with some ominous noise.
I had it rebuilt with all original 5-spd gears and 4.06 r/p. It's actually better for track use, since I can pull each gear to a higher speed, therefore don't have to shift as much in each lap. It's not a fast 0-60 as it was with 4.55, but, for me, that is pointless. It's all about lapping ! :biggrin:
SPECIAL THANKS TO BARN-MAN, THE NSX TECH YOU DREAM OF. I voluntarily drive 275 miles with my car on a trailer to get the absolute best possible NSX service in the SE.