a bloke i know who runs a real strong L20 motor has the H165 diff...he has renforced the axels so hetold me....this may be an option

why would it be nessecery to put a 9nich on a datto? they wiegh sh#tloads and would create problems with handling, unless u are getting 300BHP+ on ur datto, inst a 9inch overkill for a datto?

demo your mate didnt have a CIG locker did he?

This is my point exactly.....people hear of stories like this and dismiss the parts used as weak or no good when it was piss poor engineering. Locking diffs is stupid except for off road driving like rally and dirt track stuff and drags. There is no way in hell any diff that is locked, will handle the twisting torque for very long when driven around corners. And they screw your handling.