You can never say for sure. Those V12's were problematic. I have a E32 with 340k miles on it, and it's still running strong, altho i did replace the transmission at 200k miles. I have an inline 6 in mine tho, like i said the V12 is problematic, but as long as it doesnt have any electrical issues y ou can expect 300k miles out of it EASILY.
<img src='http://shifta.servebeer.com:8080/sig.gif' border='0' alt='user posted image' />