When I was looking in to getting a new blower motor and re-using my old cages i read some site,I think Bavarian Autosport here in NH saying the blowers with cages had the cages Balanced to the particular Motor .This suggested to me there could be imbalances when swapping cages from other motors but I found a decent used one anyway for about $80 usd which is still doing fine. Is this "balnced cage" stuff just advertising hype to induce doubts about buying just the Motor so maybe you'll buy the entire assembly ? Parts is parts right?
1995 540i Manual build 1/95