I presume youre not a fan of welded diffs then Tinytacohead, i have to say, i thought the idea was stupid, all that scrubbing and skipping when doing tight turns and couldnt see the point, until i drove with one, they really arent that bad to drive on at all.
They do take a bit of getting used to, the margin between grip and no grip is reduced, but at the same time its more consistent too in that that margin never changes unless its wet, unlike an lsd or even an open diff, bumps, road camber, tightening bends, body roll, etc, can and does make other diffs change which wheel they do or do not wish to drive, which can induce sudden oversteer as if from nowhere, with permanent 2 wheel drive that factor disappears, a far more predictable setu.
Plus it is ideal for drifting, which is something i plan to do once i have mastered the art, as im still at the stage where i apply too much or not enough opposite lock, its a learning curve, im not ready for the track yet, because if i were to bend it i would be devastated.
Tonight at a car photoshoot/meet i was at in my town there were 10 BMW's there, 2 325 saloons, 2 325 tourings, my 323 coupe (which is 2.8 powered) , a 320 coupe, a 318 compact with a 2.8 in, (all E36 shape) my old diesel E46, and a 2l E30 saloon, and another E30 saloon with a 2.5 engine in (i think) and the only 2 without a welded diff were the 320 coupe and my old 320d E46, so this alone proves that they must be OK< bacause f not then the majority wouldnt have had them.
There obviously wasnt just BMWs there though, we had skylines, an r32 gtr, another one that had loads of letters, gtst or something, a few evo's, one impreza, couple of 350z's a 2.8 capri with a welded diff (old skool cool) a sierra rs500, an RX-7, the usual saxo/corsa/fiesta people, or as we call them the'first car crowd' (everyone has to start somewhere) a bloke in a Chrysler 300C who thought he was the boy doing burnouts, that was until my american friend manny turned up in his caddy cts-v, which has had all sorts of mods and runs at about 650bhp, he didnt even need to do anything silly like a burnout, it was car of the night
Edit: this was the caddy last year, when all it had was something to do with pulleys (i dont understand) and a remap, now it has different headers, different exhaust, bigger superchargers and a better remap
http://www.youtube.com/watch?v=HfqLo-pO3F8