As we discovered earlier this month, the 2010 Porsche 911 Turbo is one heck of a fast car. The quickest Porsche has ever produced, in fact. So it would take considerable moxie to try and improve on it. Fortunately, 9ff has such moxie, as demonstrated with the company's new Speed9.

We brought you initial info on the Speedster-inspired tuner car a few days ago, but 9ff has been kind enough to grace us with a few more details on its latest endeavor. Set to be unveiled this coming weekend at the Essen Motor Show – Germany's equivalent of SEMA – the 9ff Speed9 starts with the new 911 Turbo cabrio and updates with a series of performance and body mods to take it to the next level.

Improving on the 997.5's 3.8-liter direct injection twin-turbo boxer six, the 9ff pumps output up from 500 horsepower up to 650 ponies with a simple upgrade to the ECU and new air filter, exhaust and catalytic converter. The result? Try 0-100 km/h (62mph) in 3.3 seconds en route to a top speed of 330 km/h (205 mph) – limited only by the speedster's slick open body-style. But those sleek looks and extra oomph will cost you: 239,000 euros – the equivalent of $360,000 in American greenbacks. That's two-and-a-half times the price of a stock 911 turbo cab, but if cost is no object, the Speed9 could be just your ticket.