Pat's comment? What's wrong with us having a little fun?
OK, everybody get serious now, MARS/CAP mods are only legal if you're a member of MARS but CAP uses "special" radios these days so that doesn't count. 60M is obvious and in the case of the MK2G which I own BTW you can't get 60M without opening up the transmit VFO to track the receiver. As long as you hold a license to operate it (on ham bands) owning it is legal as long as you don't transmit outside your privileges. Common sense since unless you're an Extra you can do that without modifying it, no?