"Are short scale DR Legend flats suitable for Starfire bass? Short scale strings from some manufacturers are too short for Starfire, that´s why I´m asking."
No: the silk on those particular strings (SFL-45s) lands in the nut slots. The extra distance between the bridge saddles and string anchor points on the Guild bridge is the reason for this and it is probably why some people mistakenly think that the Starfire is a medium-scale bass. This need for medium-scale strings also holds true for many short-scale basses with string-through bridges (such as the Fender Mustang).
I realize that this is an old thread, but I'm just resurrecting it to say I'm baffled as to why NS Starfire basses ship with rounds on them. Like most of those who responded above, I think these basses work best with flats (Chromes, IMHO) and also think that the rounds that the factory puts on them feel and sound like crap. Though there's really no way to know, I wouldn't even be surprised if a few sales have been lost because people tried out these basses strung with the factory rounds in a store.
OK: that's my 2¢. As you were...