I decided to take the risk and buy them as they were 150$ each. They are new. They are the exact same Michelin MXM4 that come stock with the Model S... http://www.tirerack.com/tires/tires.jsp?tireMake=Michelin&tireModel=Primacy+MXM4&sidewall=Blackwall&partnum=44VR9MXM4P&tab=Sizes My Tesla is a 2013 S60 rwd. What will happen if I install those 245 40 19 instead of the normal 245 45 19? I need someone that knows exactly the answer... The diameter difference is 3.6%. I heard Teslas wouldn't mind a 5% diameter difference. Is it true? Please advise today if possible, because I need to install tires tomorrow. Thanks a lot guys!