Like Spyderman, I'm on my second set of Pirelli P Zero Rossos on 18" Turbo wheels. I prefer these to Pilot Sports, the grip seems better in both dry and wet. Possibly Pilot Sports wear better but I feel that's largely academic as the grip deteriorates more than the P Zeros as they age. In terms of mileage I've averaged about 18,000 miles on the rears (new to 2.5mm) which has included at least three track days. I ran a fresh set (rears 150 miles/fronts 700 miles) at Castle Combe a couple of weeks back on a nice dry hot track) and it was sublime.
To answer your query about ride comfort, I've never once felt the ride was uncomfortable with P Zeros on 18" rims on the Boxster although I do tend to avoid potholed roads as much as possible.
My only issue with Pirelli has been the recent lack of availability which I understand has now been resolved.