The Cosworth Impreza STi CS400 is limited to 155mph, and can sprint to 62mph in a stunning 3.7secs, a figure that means it just about beats its nearest conceptual rival, the Mitsubishi Evo X FQ400, by 0.1secs.
The Cosworth Impreza shares more than performance figures with its Mitsubishi competitor, too; at a fiver under £50k it's within a couple of grand of the FQ400, making it the most expensive road-going Impreza ever.
Cosworth has done quite a lot of work under the bonnet to justify the price, however. The 2.5-litre turbo boxer gets a new head gasket, a high-pressure oil pump, new engine bearings, and tougher conrods and pistons.
The result of all of this is 395bhp and 398lb ft of torque, and the extra power isa dealt with by new coil springs (meaning a 10mm lower ride height), and 355mm AP Racing discs at the front.
Visual changes include a new front bumper and rear spoiler, bespoke 18-in alloys and mesh grilles on the outside, while the cabin gets new Recaro front seats and privacy glass.
Subaru and Cosworth are set to make just 75 examples, all destined for UK sale, and all finished in red, silver, or dark grey.