Rear End Instability?

[Pat]

I think thstone's post immediately above is the best response.
I've found the factory tire pressure recommendation is not my favorite. I run 34 front, 36 rear at whatever the hot pressure is in my current conditions.
I've also found the rear end gets a bit light at higher speeds. This became noticeable to me around 140 mph in a straight line. Turning while shifting would likely make this more noticeable at lower speeds.