Just in general, ebay and bmw electronic things often don't work together well.
Also, you sure it's the coils and not just the boots? I've seen so many replace coils here, just makes me wonder whether they've properly tested them or just assumed it was coil. I know coils go bad, but I also know it's rare for all six just to go...and either you or a mechanic can actually test them...don't know how...but they have their ways...you can just swap from one cylinder to another until the problem travels with the coil...
I'm so depressed. No one wants to come see me. :(
Mangofy your E46!