I replaced the OEM Bridgestone tires on my 2006 X3i with tires that are the same size 235/55 R17, service description (includes speed rating) 99 H, and similar uniform tire quality grade A A 500 versus the Bridgestone Turanza's A A 300. My dealer says I have to replace the tires to a BMW approved tire to have the car become a CPO car. The BMW CPO checklist refers to a Certified Pre Owned Operations manual - Vehicle Inspection Guidelines and Standards. Does anyone know how to see what I expect is an internal document? The dealer first said I had the wrong speed rating until I showed him that the Bridgestone and Pirelli tires they wanted me to get were also H rated, not Z rated as I think he was assuming. Then he said BMW specifies certain manufacturers. I asked to see that in writing and he said he'd have to find that document. Hmmm Can BMW restrict tires to certain manufacturers only?