dang dude. yeah, i had a 93 740il... maintenance beyond maintenance. we literally spent double what we payed for on the car in maintenance. (that wasnt even at a bmw center, i know... smack me in the head). but yeah, just know that the v12's are notoriously worse than the v8's with maintenance. when i had mine i also looked in the owners manual and the v12 is only like .1 second faster to 60 or something like that? if someone on here owns a 750 i'd like to confirm that, but its still beast!
good luck w/ the decision!