I have been a fan of the PR4s since they came out and have been fitted to the GTR, Busa, Crosstourer and FJRs. Great for the heavier bikes and un beatable in my opinion in the wet.
My only concern is how they will fair on the k1300s, as the busa suffered what i can only describe as feathering on the outer walls due to harder cornering, they only lasted 4k and got squared off pretty quick.
I have Metzeler Sportec on at the moment and they don't seem to be wearing out, great in the dry like most tyres, but yet to be caught out in the wet. Not as though i want to test them as there is a fair bit of solid rubber touching the ground without any sips, so likely to 'give' quite easily. But PR4s will be put on when i can wear these out !