I don't expect this to be a popular post, but if I was wearing out the middle of Pilot Powers before the edges, then I'd probably buy a harder, more mileage oriented tire. Soft compound tires like the Qualifiers and Pilot Powers are desirable because of their amazing lateral grip. Clearly you aren't using that part of the tire much and would probably be happier with the extended tire life offered by a Pilot Road or other similar tire.