996 and 997 GT3 cars use the Mezger engine and are manual only. 991 GT3 cars move to PDK, with the manual returning on the 991.2.
Track use is not automatically a negative, but it changes what to inspect. Look for documented rebuilds, brake history and corner-balance work.
GT3 RS and GT2 RS cars sit above the standard GT3 and are grouped with it under the GT trim family in our filters.