What do you think is the % of GT3 that never go to a track? My guess is 80%. The GT3 is a road car with some weekend track abilities. How many GT3 have a cage? 

McLaren and Ferrari sell as many convertible as coupe, no reason to think the GT3 would be different. For many the 991 GTS is too soft and not exclusive enough. I actually think they would sell at least 1/3 of GT3 as convertible if offered the choice, if not more.