I bought a 3.64 LSD for my last 535 and it seemed to me to be the perfect ratio for that car. (5 speed manual trans) I might be tempted with a 3.73 but anything steeper makes first gear useless. With the 3.64, you get just a hint of overdrive in 5th, I think about a 6-7 percent difference between the 3.46. Mine came out of a 750 and we had to swap the imput shaft. Guessed at the torque but it was working fine while I had it and the new owner has said nothing bad. Maybe we got lucky and got real close on the torque.
Mike Holbrook
Meridian, Idaho
1992 535im, 17", Euro M5 Throwing Stars 8's & 9's, FK-451 235/45s & 255/40s, M5 Sway Bars 25/20, Conforti chip, Lowes Ram Air, glass sunroof