I researched and found I needed to swap covers and output flanges which I did. I did not, however, hear that I should swap speed sensors so I didn't. How will this affect things in my '88 535is, 5spd, 3.73 LSD? Do I need to go get a sensor for the 3.73 and put it in? By the way, while I have suffered a minor loss in gas mileage, I love the 3.73 and wish I had swapped months ago. It is more fun in all gears, and even 5th has power now! Result: I go looking for curves and rice-burners!