Update!
Ok, I just reinstalled Ito's Wyvern (actually I just moved the aircraft folder back where it belongs from the "Reserve" folder I moved it to).
First, the VC is actually quite nice by Ito standards and much better than the newer design. I'm going to make some adjustments and additions to it, but basically it's a keeper. Flight Dynamics was never a strong point with Ito's work, but it was always accepted because his models are beautiful to look at and there are many talented folks here that could rework the numbers to make it better. Compared to the new version of the Wyvern, Ito's again wins out. Even though it may not be 100% spot on, the acceleration, climb rate and stability (no porpoising) were at least believable. Max speed at 10000 was1450kts which is very close to the supposed specs of this fictional aircraft.
Control surfaces animation was different. . .Ito's wings do not "sweep" like this recent versions (ala F-14 Tomcat) and the stabilators do not react to flap settings like they do in the new version. Ito's Wyvern has the normal speed brake configuration above the engine cowlings and conventional flaps, although the wingtips do fold on the ground, it has a drag chute (which I didn't try) and the weapons bays are animated and loaded.
Finally, after having flown the "New Version" first and then loading Ito's, my initial reaction as it appeared in the sim was "Wow". Ito's models are works of art and this X0-2 Wyvern is no exception. . .there is no comparison.