Jaguar North America is implementing a new policy to ensure all its horsepower ratings are expressed as DIN and SAE net before year's end.

The decision comes in the wake of a Ward's story that reveals Jaguar, in the U.S., reports horsepower ratings according to Germany's Deutsche Institut fur Normung (DIN). The problem? Some ratings for the '03 S-Type R were published without disclaimers — and DIN ratings yield sexier numbers.

Supercharged S-Type R makes 400 hp on the DIN scale while its Society of Automotive Engineers net rating — North America's standard — is 388 hp. “I think it's fair to say we needed to do a tighter job making it clearer,” says Simon Sproule, vice president-communications and marketing for Jaguar, Aston Martin and Land Rover North America.

All customer brochures and media information kits feature the disclaimer, Sproule says. But some ads and a website page for S-Type R hype its horsepower without mentioning DIN. Jaguar rejects the notion that its campaign makes unethical use of the 400 figure.

“Jaguar never changed anything from its measurement system when we introduced the R. We were reporting DIN on the E-Type.” Jaguar is equally vehement in defending the sedan's performance. It is in no way deficient, Jaguar maintains. “This is an issue about units of measurement. It's not about the car making its numbers. The S-Type R does make its numbers … whether you measure in PS, kW, DIN, SAE, whatever.”