Love(d) the Harrison line, but they must have had some goofy QC fellas, somewhere along the line. If you grabbed a handful of those Mugens, you'd probably find some with very stiff spines. Their Eclipse is that way, some with 'super' spines, yet some much softer. Sagas were also that way, but mostly on the softer side. iirc, John(golfnut2400 from FGI) actually broke an Eclipse while spining! I've had a couple stiff ones like that(did not break them tho), but also have had some that had 'normal' spines. But they all played like a million bucks....after getting them set right.
(I've yet to spine any shaft that had no detectable spine, even the wound ones. From any company.)