From illegal to legit

Hi
Everyone of us in my office is using an illegal copy of 2006 full
version. Naughty, naughty I hear you lot say. My bosses want to become
legit now and are thinking of going down the route of upgrading (as
opposed to buying a new version outright) our illegal 2006 full version
to a legit 2007LT. Bearing these facts in mind, I have a couple of
questoins to ask:
1) how 'dodgy' is it to upgrade from an illegal copy to a legit copy.
Does it make the 2007LT version legit or still 'dodgy'.
2) Could we actually upgrade to 2007LT from a 'dodgy' copy. Do you
think there is something in 2007LT that detects a 'dodgy' copy and then
refuses to upgrade the software
3) can you actually upgarde from a 2006 full version to 2007LT
(actually, I think we are downgrading by going back to LT, but I'm not
the one holing the pursestrings a nd so legit copies of the full
version of 2007 are a pipe dream.
Hope all that makes sense.
TIA
Mike