Porsche launched the Renn Sport version of the 911 GT3 at the Geneva Motor Show in 2015. Compared to the 911 GT3, the front fenders are now equipped with louvers above the wheels and the rear fenders now include Turbo-like intakes, rather than an intake below the rear wing. The roof is made from magnesium. The interior includes full bucket seats (based on the carbon seats of the 918 Spyder), carbon-fibre inserts, lightweight door handles and the Club Sport Package as standard (a bolted-on roll cage behind the front seats, preparation for a battery master switch, and a six-point safety harness for the driver and fire extinguisher with mounting bracket). The 3.8-litre unit found in the previous 997 GT3 is replaced with a 4.0-litre unit that has a power output of 500 PS (368 kW; 493 hp) and 460 Nm (339 lbft) of torque. The transmission is PDK only. The car accelerates from 0–100 km/h (62 mph) in 3.4 seconds (0.6 seconds quicker than the 997 GT3 RS 4.0) and 0–200 km/h (124 mph) in 10.9 seconds. The 991 GT3 RS also comes with functions such as declutching by “paddle neutral” — comparable to pressing the clutch with a conventional manual gearbox – and a Pit Speed limiter button. As with the 911 GT3, a rear-axle steering and Porsche Torque Vectoring Plus with fully variable rear axle differential lock are available as standard.
In February 2018, Porsche introduced a facelifted GT3 RS model to continue their updates for the 991 generation of the 911. Changes include a new engine similar to the GT3 and RSR models with a 9,000 rpm redline and a 20 PS (15 kW; 20 hp) and 10 N⋅m (7.4 lb⋅ft) increase over the outgoing model, NACA ducts for brake cooling, modified front fascia (similar to the 991.2 GT3), side skits and rear wing (similar to the GT2 RS) for increased downforce, ball joints on all suspension links, front helper springs, lightweight glass for the rear and rear-side windows and a newly developed tyre compound. A Weissach package was available that included additional carbon fibre body and interior parts as well as magnesium wheels and stiffer suspension settings is available as an option.