76CSX and CN 2008 (regular vs NT) and (MicroSD vs DVD)

I have a 76CS now. With CN v8 unlocked to it.

I just got the CN 2008 upgrade disk yesterday and installed it on the PC.
But, I haven't unlocked it and paid the $70 because I am going to
order a 76CSX tomorrow.

I assume this was the right move? (not unlocking yet)

So, the question(s) are:

I know I should wait until I have the 76CSX in hand and unlock 2008 upgrade to
it, if...

Question #1 is: Will Garmin even let me UPGRADE 2008 to a BRAND NEW unit, or do
I have
to buy the full version of 2008 because it is a totally new unit?

Question #2 is: IF I have to buy the full version, is there a compelling
advantage to using
CN 2008NT on a 76CSX instead of plain old CN 2008?

Question #2.5: IF I have to buy a full version, the dealer I'm buying the CSX
from has the
NT microSD in stock - the DVD is backordered. So then it becomes the question of
DVD vs pre
loaded card. I assume I can pull the maps from the card to the PC for browsing
maps, routing, etc?
So, what are the advantages / disadvantages of each media?

Question 2.75: If DVD is the most desirable, can I still use my 2nd unlock on my
CN v8 to load maps
on a temp basis to my new 76CSX until the CN 2008NT DVD arrives? Or has that now
changed too?

I hope all of the above makes sense...

All insights, observations opinions and advice, etc. welcome. ASAP, 'cause I'm
'pullin' the trigger'
on all this tomorrow morning.

BTW: Anyone want/need a mint 76CS??