Tire threads are getting to be a lot like oil threads. 😋 The non-GT versions aren't for heavy bikes like the FJR. Michelin PR4 and PR5 shine when you ride under all conditions including frigid and/or wet. Since tires are about prioritizing and balancing, they do sacrifice some cornering-acceleration on warm/hot pavement. In that regard the 5s are an improvement over the 4s. Fully leaned on a few sets and haven't detected any performance or durability difference when the leading edge of the tread raises; no reason to obsess or sweat it. Just rrriiidddeee. If you're smart and only ride under ideal conditions, a different tire can be a better fit. If you're a bit of a stubborn iNtUiT, the PR4 and PR5 can be the safer choice.
EDIT: BTW, I use Castrol. 😜