German tuning company 9ff has once again underlined why it’s widely considered to be the world's leading Porsche tuner – unleashing a souped-up version of the Porsche 997 that we consider to be one of the most beauteous Porsches we've ever seen.

9ff has made adjustments to both the 997 cabriolet's exterior and its powertrain, using classic Porsches such as the 1989 911 Speedster, 1993 964 Speedster and the 356 as a source of inspiration.

Notable changes to the exterior include altered front and rear bumpers, a shorter windscreen, deeper sideskirts, and a large rear panel that accommodates the folded convertible roof.

After 9ff has tinkered with it, the 997's 3.6-litre, twin-turbo powertrain now has a power output of 650bhp, up by a mind-blowing 180bhp from that of the basic model. This significant power increase has been achieved thanks to the introduction of a pair of 9ff F650 VTG turbochargers, a reprogrammed electronic control unit, a sports air filter and a sports catalytic converter.

The jury's still out on whether or not it’s better than the 2008 Porsche 9ff GT9 – the world’s fastest Porsche – but the 9ff Speed9 definitely ranks up there as one of the finest Porsches to have come out of the 9ff garage.

Judge the 9ff Speed9 Porsche 997 Turbo for yourself by checking out the gallery below.