Here are some answers:
1/ The Amvox 1 is not a limited edition unless it is in Titanium ( 1 000 pieces ).
A Special Edition, that means that the production was limited, but no one knows the real numbers.
My guess is that it would be around 5 000, maybe 6 000.
It doesn't have any value implication, and if you want to do an investment, you should avoid watches in general.
2/ Yes, the Amvox I is discontinued, since 2009, if I remember correctly.
3/ General thoughts about this watch:
This is a modern interpretation of the Polaris, a very cool watch, with a reliable movement.
If you're in love with it, you should just go on it, withouth thinking about its value in the future.
As always with watches, when the deal is too good, the deal is not good.
Buy the seller, even if it costs you a bit more.
Best, and welcome here!
Nicolas