BREAK OVER; the Cadillac STS returns, this time as a rear-driver.(News)

Byline: BOB GRITZINGER

After a 16-month hiatus, the Cadillac STS returns to the market this fall as a rear-wheel-drive luxury performance sed-an-one Cadillac dares to compare to the best the marketplace has to offer.

"We think we've narrowed the gap,'' promises Cadillac general manager Mark LaNeve, with competition that includes the BMW 5 and 7 Series

(Cadillac believes the car falls squarely between the two BMW models), Mercedes-Benz E-Class, Audi A6 and the Lexus GS 300 and LS 430.

We haven't driven the all-new STS yet so we can't speak to that boast, but we're betting once we do get behind the wheel we'll find the car much improved dynamically from the outgoing front-drive model, which ceased production in May 2003.

For 2005 STS arrives on the Sigma platform, the same chassis underpinning the rear-drive CTS and performance variant CTS-V, as well as the rear- and all-wheel-drive SRX sportwagon. STS will be offered in rwd with awd available on V8 models-the first General Motors rear-drive sedan with an awd option. STS joins a Cadillac showroom now weighted heavily toward rwd and awd vehicles, once you add the Corvette-based XLR luxury sports car and Escalade sport/utes. Only the Deville remains front-drive, and Cadillac is still mulling that car's future layout, though it appears likely the big luxury liner will remain in the front-drive family.

At first glance STS appears nothing more than a super- sized CTS, which is part of the plan to continue building on Cadillac's now-established "edge'' design character, says Kip Wasenko, STS lead designer. But a closer study (you will get a chance at the car's premier at the New York auto show) reveals significant differences-softened fender creases, sculpted wheel arches and more fluid C-pillars tucking into the aluminum rear decklid-all intended to convey a more refined evolution of Cadillac's styling.