all the hydro trannys are built basicly the same. the jdm cable trannys (j1, y1) have smaller main and countershafts.

as for the lsd.. the weak part of a honda tranny is the DIFF carrier. they flex and break or they flex and the spider gears break. the ONLY way to fix that is with a aftermarket diff. im partial to the quaife b/c of the lifetime warranty. then syncros are all made of the same stuff as are the gears etc etc.... yes the itr tranny has a lsd but it will break just as fast as a non lsd diff.

installing a diff isnt that hard. get a helms manual and take your time.