I just got word that Magnepan is doing a transferrable Warranty program for those that trade-in their 1.7s for new 3.7s at their dealer.
The remainder of the 3 year Warranty on the 1.7s gets transferred to the "new" owner. If they're 6 months old, you get 2.5 years worth of Warranty, a year old you get two years, you get the idea.
This is a limited time deal and you now know as much as I do.
Good way to upgrade whether you're trading 1.7s in or buying them used.