My Buddies and I were talking about this as well.
More for the fuel injection part of it.
our thoughts were ...
is the Rune the Same Frame as the Valk ? or is it like the GL1800 Aluminum?
Is the Rune the Same Exact engine and the GL1800 or was this an early version ?
The Rune frame is different than the Valk by a far shot. Whether it's the same as the wing, I can't say.
I also can't say about the engine, but I BELIEVE (just a belief... I'm not sure) it's the same 1800 wing engine with a different fuel map.