According to The Car Connection, the IS500 will probably receive the 4.6-liter V8 from the new Lexus LS460 (wouldn't that make it an IS460?), which would up the power to around 380 horsepower.

Consider the mobile CD player that is the Lexus IS500. If you want entertainment ... the CD player might be more compelling than the engine; that certainly applies in the less-powerful IS300 ...

of torque, which is a larger and more powerful engine than the 380-hp ... think are official shots and specs of the forthcoming Lexus IS500. While these images could be nicely done Photochops ...

This is the Lexus IS500 F Sport, a high performance derivative ... compact rear-wheel drive chassis and a naturally aspirated V8 engine. We say frustrating because it’s a combination we ...