Hi Philip,

There's quite a bit of info on upgrading at

http://www.projectpluto.com/upgrade8.htm

(how to do so, what it costs, what you'll get, etc.) To
answer one obvious question up front: the fact that you've
skipped a few versions isn't a problem. I think I've had
at least one person upgrade from Guide 2 to Guide 8. A bit
of a large leap (Guide 2 was very much the "state of the art"
in 1993, but looks primitive now), but there's no barrier
to making that leap.

-- Bill