There's one dealer that gives great discounts to 8-series owners on parts for their cars, although I think you have to provide proof that you actually own an 8 series to get the discount. This dealer is where I get all the parts I need for my '94 840, basically at cost. The only high-$$$ part I've had to get so far was a fuel pump assembly (knock on wood).
Maybe hunt around on BMW forums / roadfly for something similar? Some sort of BMW club you can join that has an agreement with certain dealers for a parts discount?
Nice E34, BTW :thumbsup: