well the ruf rgt sucks its ugly as hell, if only they put the gt3 in which is WAY better, and nigma is right u cant tune the porsche gt3, but u can tune it before u replace it with the actuall car,
for example: buy a fully moded RUF CTR 2 then tune it to some certain specs (usually one that fits almost all tracks), then when u shark in the gt3, the settings stay the same, thats the only way i think u can do it....