I called a few shops to get some pricing, they seems to be on par other than the dealer being double on the parts at least.

One question though is that my original guy wants to filter the oil and reuse it. He said that's bmw recommendation. Another guy says to use new oil because it's contaminated. what is right way?

I mean if my transmission is leaking some oil and the guy needs to use the same oil, shouldn't he have to top it off after with new oil.