Re: Fitting a LSD/Q2 diff.
5-pot does sound a lot nicer, you're right there. The 4-pot sounds like any other 4-pot diesel on the roads, but there isn't much a manufacturer can do to make a diesel sound different anyway. The Beemer 6 cyl is a nice sounding thing, for a diesel anyway.
I mis-directed my first post by the way, the bit about it not fitting the 20v six-speed should have been follower by the quote from PC7671. who said "the six speed box is the vital component", which is a bit misleading as it fits the 10v 5-speed, 16v 6-speed and V6 6-speed but not the 20v 6-speed.