Ok dont be scared to open the box yourself. I opened mine for the first time and replaced my LSD with the Mfactory one. I accidently droped the gear shaft and all of the gears and sincro's fell apart and i was thinking how the fek would i put all this back together. Found a workshop manual on the net and i just had the order and i just placed it back together and its fine.

Theres alot of small tricky things when opening the gearbox which i had problems with but i got a video off stefan (zeforce) which he also used. Its a step by step guide into replacing gears and change the LSD in a b series box.

Im pretty sure all the b16 series boxes are similar in make but the only difference is the gear ratio's in some. I have been told that the tyre R ratios are alot smaller and are good for track but not for drag.

You might be better off just getting an LSD and some new syncro's. Will be alot cheaper than buying a type R box.