The 991-codenamed GT3 RS is a lightweight track-focused model that was offered in Porsche's 911 model lineup for the 2015 to 2017 model years. Following the tradition of Porsche's RS (Rennsport) cars, the GT3 RS draws power from a naturally aspirated flat-six engine bored out to four litres. It revs up to 8800 rpm and produces 493 hp.