If you are not making payments on any of them, don't sell them just yet. You may not be able to get as much $$ for them as you would like, and then you would have $$ but no toys...

The Katana probably has the best chance of selling, being more of a 'rocket' and therefore more exiting to a younger, more impulsive buyer with some spending money burning a hole in his pocket.

The Silver Wing is a lot like the 240D in philosophy if you think about it, both are 'basic' and simple while accomplishing their core mission.