The Audi SQ5 is the first ever diesel 'S' model in the makers history. Audi made history in 2006 when it won the famous Le Mans 24hrs race with diesel power - now the German manufacturer has decided to make a performance diesel SUV. The SQ5 is the quickest car on the Q5 line-up while it also has the most power. Not many rivals exist in this sector, performance SUVs are a niche market but rivals including BMW X3 xdrive 35d M Sport and Porsche Cayenne V8 diesel will be looking over their shoulder. Can the Audi SQ5 go straight to the top of the class? Read on to find out. Performance One engine is available on the Audi SQ5 and comes in the guise of a 3.0-litre bi-turbo diesel unit with a power output of 308bhp. It's quick too - getting from zero to 62mph in 5.1 seconds and has an electronically limited speed of 155mph. The diesel engine is mated to an eight-speed tiptronic semi-automatic gearbox with paddle-shifters located behind the wheel. For a big car the SQ5 has plenty of torque - 650Nm of pulling power on tap means that overtaking slow moving traffic on single lane carriageways. Over the benchmark sprint from zero to 62mph - the Audi SQ5 can complete the dash in 5.1 seconds whereas the BMW X3 xdrive 35d M Sport completes the 0-62mph in 5.8 seconds while the Porsche Cayenne V8 diesel can complete the benchmark sprint in 5.7 seconds. Ride and Handling The Audi SQ5 feels nimble and agile for such a sizeable car. On twisty b-roads the Audi SQ5 is good fun but it is not as driver focused as a BMW X3 xdrive 35d M Sport but it is quicker than both the BMW X3 xdrive 35d M Sport and the Porsche Cayenne V8 diesel. Sporty characteristics are already running through the Audi SQ5 with the epic straight line speed, however, it is better than the standard Q5 around the corners thanks to being lowered by an extra 30mm. The Audi SQ5 comes Audi drive select offering a choice of five modes, Comfort, Auto, Dynamic, Efficiency and Individual allowing for greater customisation. Four settings are available comfort, auto, dynamic and individual. When the dynamic steering option is not specified then these same settings can be applied to the steering weighting, along with the eight-speed S tronic transmission's shift points and the throttle response. Quattro permanent four-wheel drive also comes as standard on the Audi SQ5 - handy in adverse conditions. The BMW X3 and the Porsche Cayenne have still got the upper hand on driving dynamics but the SQ5 has brought the Audi closer to its rivals in terms of pure driving enjoyment. Comfort and Practicality Audi SQ5 comfort levels are superb if you keep the car in 'comfort' mode. This quick version of the Q5 makes light work of traffic but it is also very good at 'pootling' through town centres. You can switch to 'dynamic' mode but we'd recommend to use this function when on your own and on challenging roads to reap the benefit. Audi SQ5 practicality levels are very good with ample space both up front and in the rear. With the rear seats in place the Audi SQ5 has a load space of 540 litres and when folded this expands to 1,560 litres. Running costs Audi SQ5 prices start from £44,055, that's more expensive than the BMW X3 xdrive 35d M Sport but the Audi is quicker from a standing start to 62mph by 0.7s. When comparing with its key rival the BMW X3 xdrive 35d M Sport pips the Audi on claimed average economy and is also cleaner. The Audi SQ5 has an average economy of 41.5mpg and emits 179g/km of CO2 while the BMW X3 xdrive 35d M Sport averages a claimed 46.3mpg and emits 163g/km of CO2. The Audi SQ5 is packed with plenty of kit thanks to being the flagship model on the range. Equipment highlights include 20-inch alloys, xenon headlights with auto headlight-range adjustment, headlight washers and LED daytime running lights, Quattro four-wheel drive, S sports suspension, three-zone climate control, cruise control, light and rain sensors, Bluetooth, rear parking sensors and DAB radio. Summary The Audi SQ5 is the flagship of the Q5 model line-up and if you are intent on buying this version you will not be disappointed. Are there more driver focused cars in the class? Yes, however, this mixes good comfort levels with outright pace. The Audi SQ5 starts from £44,055 and is on sale now.