as far as i know the N62 engines have seen no update during their lifecycle in the E70s. any 4.8 you can buy will put you in with the chance of having to have the valve stem seals fixed. and the valley coolant pipe.
unless you get one that already had those done.
people also report issued with the M57s, N52s and N55s as well as the N63s. take your pick of problems you'd like to fix
