The Porsche 911 GT3 (991) is a track oriented variant of the Porsche 991 generation 911 lineup. Its engine is based on that of the 991 Carrera S, but with little shared parts. Other features of the car, such as its crankshaft, were developed specifically for the car. The 991 GT3 is the first Porsche to use rear-axle steering technology and is only available with Porsche's PDK transmission unlike its predecessors.