Hennessey has taken the Ford Focus RS to new performance heights.

American tuner Hennessey Performance has introduced a more powerful version of the Ford Focus RS dubbed HPE400.The HPE400 retains the RS' turbocharged 2.3-liter four-cylinder engine, but Hennessey has upgraded the engine management software, added a high-flow air filter, and installed a stainless steel mid pipe with an electronic dump valve. The modifications bump the turbo four's output up to 405 horsepower and 425 pound-feet of torque, increases of about 55 horses and 75 pound-feet of twist over the stock model.

Performance specifications haven't been announced yet. Hennessey's hot-rodded RS retains the stock model's six-speed manual transmission and all-wheel drive system, which is capable of sending up to 70 percent of the engine's torque to the rear axle.

The parts required to turn the Focus RS into a Hennessey HPE400 are bundled into a kit that retails for $2,995. Alternatively, Hennessey will install the parts in-house and run the car on a dyno for $4,995.

Buyers who want more than 400 horsepower are in luck, because it sounds like Hennessey is developing more performance parts for the RS. These include upgrades to the intercooler and turbo systems, as well as new wheels and tires. Brake and suspension modifications will likely join the catalog of aftermarket parts, too.