Hey everyone....So I have a 2015 428i xdrive M sport coupe convertible; I had my car into dealership today for her 20k maintenance and was told I need new front rotors and brakes....so I'm looking to DYI (or rather my husband do it) but I have no idea what size rotors to go with as there are 2 options; 312mm or 330mm....If anybody can answer this question I would greatly appreciate it!! Thank you!!
