Today, 06:19
Jan,
No, the FSX version won't work in P3D, at least not in P3Dv4.5. Believe me, I tried. I can't recall now what the issue was, it was a few years ago. Maybe it would work in the 32-bit P3D versions up to v3 if you could "find" a copy. But those have no native VR support I think, so you'd still have to use FlyInside and I wouldn't see much of an advantage over FSX.
FLyInside is available for P3D up to v4, and the guys in the support forum are begging for a v5 version. I don't really see why, P3D's native VR support in v4 and v5 is fine, maybe FlyInside has a few extra features but wouldn't be worth the hassle IMO. Maybe they have headsets that P3D doesn't support. P3D only uses SteamVR which is perfect for our Reverbs.
Same for the Sabre. I think the FSX port for that...