Hi Leaf and welcome to the forum.
It looks like you've done your homework and have a good idea of what needs to be done. So this sounds like a personal decision.
On one hand, you can save over a thousand in exchange for a pre-aged hull with a full two year warranty (boat and Drive) that probably offers just as much fun on the water and that no-one will want to steal.
On the other hand, you can get the newer, updated version that has some convenience and durability upgrades -- for 50% more money.
Economic limitations aside, if the boat is likely to get scraped up in use, it probably makes more sense to get the older hull. If you are planning to do a lot of pedaling and want to upgrade the Drive, you've got a nice pool of money to so it with.
On the other hand, if you're a spit and polish sort who gets a lot of enjoyment from the visual aspects, you might regret not getting the newest boat.
Since you're the only one who has personally inspected this boat, you would know best where the value lies!
Remember you may want some accessories -- Turbofins, cart and ? Either way, it adds to the price.
Whichever one you get, you should have a blast sailing it!
PS is it feasible to take the '07 on a demonstration run to make sure there is nothing warped and everything is fully functional? I'm thinking about the rudder assembly in particular after baking in the sun for a couple of years or with the weight of the boat on it. It is replaceable though.