[fel64]

1. Unfortunately there’s nothing I can find. No-one on these forums has posted about switching from vBulletin yet, presumably because they’ve invested in it. I can’t help since, well, it’s licensed. Maybe you can look at the data structure yourself and write a converter?

2. No idea, but my guess is far better for performance. That’s one of the main reasons for bb’s existence – to provide even faster forum software than the best the WordPress people could get their hands on.