i'm new to the x5 discussion, but not the forum. had an '01 740il, but she gave up the ghost and i didnt want to put a new engine in her. anyway, i own a 2013 x5 x35i. had 28k miles on it when purchased and now time for an oil change at 30k. i'll stick with the castrol brand, but whats the consensus as far as weight? thanks.