As CN90 states, there is a wide variance in the quality of rebuilt electrical parts. I have only had good luck when I purchased rebuilt electrical parts either from the dealer (BMW/Honda/Nissan) or from an online retailer that sells products rebuilt by the oem manunfacturer (or their designated contractor), example: Bosch rebuilt alternator, or Nippondenso rebuilt starter.
Rebuilt stuff from chain storres, and independants can really vary in quality, depending on who is doing the work. Typically the chain store stuff is the worst, as they are driven by a national contract, and price is king, so they only replace what is absolutely necessary, then clean it up and paint it, put it in a box and say "lifetime warranty".
I got my rebuilt alternator for my 540 from BMW Seattle, they installed it too (emergency repair) and it was super expensive, but comes with a "lifetime warranty" that is honored at any BMW dealer in North America, parts and labor. So I basically paid $300 extra over the online price for the lifetime warranty versus the two year warranty that Bosch offers (it is the same exact Bosch factory rebuild). My understanding is if you buy the alternator from BMW "over the counter" and dont have them install it, their standard 24 month unlimited mileage warranty applies (parts and labor), not the lifetime warranty.
I have about 80k on that alternator, and hope to keep the car long enough to get my $300 back out of BMW!
Factory M-Sport package with factory installed M-tech bumpers, factory Bluetooth, factory M-Audio 10" dual voice coil subs, Homelink, M5 rear stabilizer bar, Bilstein B14 PSS coil overs, Stop Tech ss brake lines, Akebono Euro Ceramic brake pads, oem Brembo and Zimmerman rotors, Dinan Stage 1 software, Strong Strut front upper stress bar.
Last edited by 540 M-Sport; 09-16-2010 at 11:13 AM.