I went to my dads shop in order to put the car on the lift, with his help do the front brakes and find what the scraping noise from the back was ... and we find the guibo completely torn up. my dad says "i got a tranny from a cadillac catera i took off last week and it has a new guibo ... and i think its the same" ... take that off, we take off the one off the 535 ... and yup, exactly the same apart from one saying gm and one saying bmw ... same bolt pattern, same thickness, same middle, driveshaft hole.
saved 40 dollars. great stuff.