Upgrading from e53 - issues to watch

[Russianblue]

There are a few of us here lurking in search of a definitive 'issues to watch out for' thread whereby we can make the decision to move from an e53 to an e70.

I would love to know the imperative issues (M20 timing belt style) that simply MUST be addressed as well as the gotchas and "just keep an eye on" type things.

If there's a single post outlining this stuff, I'd love to know where it is.

I'm going for low cost of ownership frankly given that I do most of the work on my e53. I assume brakes and suspension are pretty close. what about engine, tranny, A/C, electricals and stuff like the e53 door handle carrier insanity?

thanks!