The Saleen S7 Twin Turbo was an updated revision of the original S7. The twin-turbocharged version went on sale in 2005 for $585,296 USD, replacing standard S7 production. Then engine boasts two Garrett turbochargers producing 5.5 psi (0.4 bar) of boost, increasing the maximum power to 750 horsepower (760 PS/559 kW) at 6300 rpm, and the maximum torque to 700 lb-ft (949 Nm) at 4800 rpm. The front and rear diffusers and the rear spoiler were also reworked to increase downforce by 60. It has a top speed of 248mph. Continue reading for more.

5. 9ff GT9-R – 257mph

The 9ff GT9 is a sports car based loosely on the Porsche 911, built by German tuning company 9ff, founded by Jan Fatthauer. Based on the Porsche 911 (997) GT3; the cars 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. The 9ff GT9 was replaced by the GT9-R, offering up to 1,120 bhp (840 kW; 1,140 PS). It was designed to take the speed record for a street legal car, with a claimed speed of 414 km/h (257 mph). It does 0-100 km/h (62 mph) in 2.9s and 0-300 km/h (190 mph) under 16s. As with the original GT9, only a limited number of GT9-Rs were produced and only 20 with the largest engine.

4. SSC Ultimate Aero – 257mph

A 12-mile (19 km) stretch of U.S. Route 93 in Nevada was closed on March 21, 2007 to allow SSC to test the Ultimate Aero TT, but the attempt was called off due to bad weather. An effort the following day failed due to sub-optimal conditions, test driver Rick Doria reporting “wheel-spin” at speeds above 190 mph (310 km/h). Six months later SSC announced they had established a new production car speed record of 256.18 mph (412.28 km/h) in West Richland, WA on September 13, 2007. In accordance with FIA Speed Records rules it was an average of two runs in opposite directions, 257.44 mph (414.31 km/h) and 254.91 mph (410.24 km/h). The results were verified by the Guinness World Records on October 9 2007.

3. Koenigsegg Agera R – 260mph

The 2013 version of Agera R premiered at the 2012 Geneva Motor Show. Upgrades include, but not limited to, carbon fiber wheels, enhanced aerodynamics, and engine upgrades allowing the Agera R’s 5 litre twin turbocharged engine to produce 1140 hp on E85. And, thanks to Koenigsegg’s pioneering Flex Fuel Sensor technology, the ECU can respond (practically instantaneously) to varying fuel qualities and alcohol content by reducing power levels as a means of protecting the engine. On standard low octane fuels, power is reduced to 960hp.

2. Bugatti Veyron Super Sport – 268mph

The Bugatti Veyron EB 16.4 is a mid-engined sports car, designed and developed by the Volkswagen Group and manufactured in Molsheim, France by Bugatti Automobiles S.A.S. The Veyron features an 8.0-litre, quad-turbocharged, W16 cylinder engine, equivalent to two narrow-angle V8 engines. According to Volkswagen Group and certified by TUV Suddeutschland, the final production Veyron engine produces 1,001 metric horsepower (736 kW; 987 bhp) of motive power, and generates 1,250 newton metres (922 lb-ft) of torque. The Super Sport version – driven by Top Gear’s The Stig – achieved the fastest ever time of 1:16.8, as well as being taken to a (verified) average top speed of 431 km/h (268 mph) by Raphanel on the program.

1. Hennessey Venom GT – 270mph

The Venom GT uses a highly modified Lotus Exige chassis. The manufacturer, Hennessey Performance Engineering, claims the modified chassis utilizes components from the Lotus Exige. The Venom GT is powered by twin turbocharged 7.0L [427ci] GM LSX V8 engine with an iron block and aluminum heads featuring twin precision ball bearing turbochargers. The engine produces 1,244 bhp (928 kW; 1,261 PS) of power at 6,600 rpm and 1,155 lb-ft (1,566 Nm) of torque at 4,400 rpm. Engine power output is adjustable by three settings: 800 bhp (597 kW; 811 PS), 1,000 bhp (746 kW; 1,014 PS) and 1,200 bhp (895 kW; 1,217 PS). The engine revs to 7,200 rpm. On February 14, 2014, on the Kennedy Space Center’s 3.22-mile shuttle landing strip in Florida, the Hennessey team recorded a top speed of 270.49 mph (435.31 km/h) with Director of Miller Motorsport Park, Brian Smith, at the wheel.