Originally Posted by rob_h10
Here's what worked for me; BMW has an EKT catalog that is available online (google is your friend) and i used that to cross reference the M Performance suspension parts - the springs - that was required for my car (you have to provide your vin).. then i went to the dealers parts dept and had them check my research. They then used their BMW EKT catalog access to determine and verify the required parts for my M suspension retrofit project. And every part number matched exactly.. btw, that's where I learned that the stock ARB's did not have to be replaced.
correct....You already have sports suspension, thus you do not need the ARB's. With stock suspension, you must upgrade the ARB's.
Springs need to be upgraded regardless of what suspension you have.