I have fitted 195/65R15 tyres on my 2008 Plus 4 4-seater in order to gain more ground clearance. Combined with AVO's up front my ground clearance issues were solved.
I think you should really press the car to the limit to feel any performance difference with respect to grip. Of course, there will be about 3-4% higher overall gearing. The only noticeable side-effect is that the speedometer now is exact. Here is a
side view of the car.
Harald
