[su5331]

I have a 2009 328xi.

I asked my dealer about brake fluid change.

They said brake fluid costs 125$ and I also need change micro filter which costs 132$. the advisor said I need to change the filter at the same time.

I asked an independent specialized repair shop. They said brake fluid is 108$ and filter is 90$. But I am worried about the independent shop since I have not been there, and I do not have many reviews about the shop.

I also have a cpo warranty. Is my warranty going to be void if I get service at the independent shop? they said they have key reader system, but it is now out of control...

help me people, I really don't know what to do.