DETROIT — After a blistering performance at Germany's Nurburgring circuit, Cadillac's upcoming 2006 STS-V earned official power ratings of 469 horsepower and 439 pound-feet of torque at 3,900 rpm. The company says that's the most output ever for a production Cadillac. Production of the STS-V, the latest edition of Cadillac's V-Series, is slated to begin this fall. The STS-V features the new 4.4-liter supercharged Northstar V8 engine and GM's new Hydramatic six-speed automatic transmission. Cadillac had expected the engine to produce about 440 hp. Cadillac is the first automaker to begin using the Society of Automotive Engineers' procedure — basically third-party witness testing — to certify power for its new engines. The supercharged Northstar V8 will also power the upcoming V-Series edition of the XLR roadster slated for production in early 2006. The XLR-V is certified at 443 hp and 414 lb-ft of torque at 3,900 rpm. The engine generates more peak power for the STS-V due to the greater underhood space that allows more induction and exhaust capacity, Cadillac said in a statement. What this means to you: Cadillac's impressive V-Series will now consist of three serious performers, all going zero to 60 in under 5 seconds. Not sure about the algebra, but will V ever equal M or AMG?