Porsche 997 9ff GT9 are extensively rebuilt and fitted with a heavily modified 4.0 litre flat 6 that produces 738 to 1,120 bhp (550 to 835 kW; 748 to 1,136 PS), depending on the configuration. One of the major differences from a normal 911 is the positioning of the engine; whilst every 911 throughout Porsche's history (excluding the Porsche 911 GT1 racer) has been rear-engined, the GT9 is mid-engined for better weight distribution.
It takes the Porsche 997 9ff GT9 3.8 seconds (from a rolling start) or 5.2 seconds (from a standing start) to reach 100 km/h (62 mph), and 17.6 seconds to reach 300 km/h (190 mph). The top speed of the original GT9 is 409 km/h (254 mph).