I have a set of 208gp's on my 748 at the moment, great on track but totaly unsuitable on the road, unstable on anythink but smooth tarmac. The Conti's are designed I believe by the guy that designed the Diablo's, so it will be a good tyre.
Going on the difference between the 208's & the Diablo's it would be the diablo's every time.
Chris.