American Generation One Autobot Giftsets

As I am finishing up my American G1 collection one of the last things on my list are the giftsets. I've had the easy-to-find Superion giftset for a very long time now, at least three or four years; but Defensor and Computron have always eluded me as being either too expensive or completely unavailable. But as things tend to do, it always comes in waves...