**All high speed antics are performed in a controlled environment, so save your flames for the squids**
When you say "sport tourer" you mean FZ6R, FZ6, FZ1, etc... yes? I have never ridden a super sport in anger, so I have no basis of comparison, but I have found that hanging off on my FZ1 works better. I have gone through turns pretty quickly with my butt centred on the seat, using my feet and upper body to shift weight, and it works fine. The bike feels stabe and planted and rips through turns at some eye-opening speeds. I feel that hanging off gives me more margin for error at the same speed, though. The bike stays more upright and leaves more room for correction. Or, if I really feel like pushing, I can improve my cornering speed noticably by hanging off and pulling the bike right over. It feels pretty cool when you're one cheek on, knee out, with your head directly in line with the mirror and the bike leaned right in. I hang off even when riding easily on the twisties now, because keeping the bike as upright as possible and using my body to turn seems to give me way more room for emergency adjustments.