Jaguar is well-known for making the best – or should we say least worst? – diesel engines. They are potent and economical, and overall more refined than you would expect. But they are now being outdone by TDI-Tuning who has managed to improve an XF saloon beyond anything Jaguar themselves would have deemed possible.

The secret TDI-Tuning uses to turn Jaguar XF into a real sports saloon is called CRTD2 Twin Channel Digital Diesel Tuning Box. It needs a long name because this box of tricks enables the 3.0 liter V6 diesel engine in the XF to develop an extra 70 brake horsepower, while making it more fuel efficient by 4 to 6 mpg. That, you would agree, is amazing.

So your Jaguar XF 3.0 V6 diesel comes to TD-Tuning workshops with 271bhp and 443lb ft, and it leaves it with 341bhp and 514lb ft. It is now faster by 10 mph and more agile, and yet it burns less fuel and produces less CO2. And all it will cost you is £300.

“Long gone are the times when premium brands considered diesel derivatives the poor relation,” says TDI-Tuning Principal Graeme King. “Recently, the new Jaguar XE won ‘Best Large Car’ in the 2015 Diesel Car magazine Awards, beating the equally prestigious BMW 3-Series. Fuel economy and performance are no longer mutually exclusive, and owners still look for ways to improve both.”