Buying an XK8

[AndrewL]

Hoping to buy an XK8 soon. Budget is <£18000 so it will probably be a 4.0. What should I go for? a newer car with more miles or the lowest possible mileage? I know sevice history is important. Is it worth paying main dealer prices for the warranty or are these cars reliable? What should I look for when I go to view ?
Any help appreciated
AndrewL