Currently, I'm using a Pilot Road 3 on the rear and a Pilot Power 3 on the front because the Pilot Road 4 wasn't available when I installed them. They are taking forever to wear down but once they do, I'll put a Pilot Road 4 on the rear and stick with another Pilot Power on the front.
I'd used Michelin Pilot Roads on my CBR1100XX and FJR1300 for a combined 135,000 miles and always used the newest model that was available from Michelin. In my experience, the newest version always outperformed the previous one and never felt the need to use a Pilot Road rather than a Pilot Road 2CT or a Pilot Road 2CT in lieu of a Pilot Road 3.