Detroit carmakers are flexing their collective muscle more than ever for 1989, sending out a strong message to buyers that style and performance are once again in the driver's seat for 1989.

The new cars being offered by General Motors, Ford and Chrysler are in stark contrast to the boxy, fuel-efficient ones offered as this decade dawned 10 model years ago.Threats of soaring gasoline prices were foremost in motorists' minds back then. However, those dire predictions never came true.

But Detroit's carmakers were inexorably locked into designs which foisted small, dull-looking conveyances upon a public rapidly tiring of cramped, underpowered cars.

Inklings of bold new designs - like the Ford Taurus or Chevrolet Beretta - have seeped out of Detroit's design studios in recent years. It seems the spigot has now been opened a few more turns, as larger cars with a bit more flair are becoming more the rule than the exception.

Looks, after all, still play a major role in a buyer's purchase decision.

So does power, despite warnings by industry analysts that carmakers are beginning to show a lack of regard for government-mandated fuel economy standards by offering an increasing number of more powerful and less economical engines.

Quality is becoming less of an issue as the 1989 model year unfolds. That's because it's getting hard to find a car that is not well made. Sure, there is the occasional lemon, and some cars are built using newer technology than others. But overall, quality levels are the highest in history.

Also at their highest levels are the use of electronics and on-board computers. That is sure to limit repairs and maintenance by do-it-yourselfers to changing a light bulb, changing the oil, or its filter - if you can find it.

The new model year also brings a wider use of air bags and automatic seat belts under a federal requirement intended to provide motorists with safer cars. Anti-lock brakes, which prevent the wheels from locking up under hard braking to maintain vehicle control, are also appearing in greater numbers as their cost slowly comes down.

Ford, heralded as the world's most profitable carmaker, has redesigned its Thunderbird and Mercury Cougar coupes from the ground up for 1989 to give them a longer, lower and wider appearance - although they are really about 3 inches shorter than the 1988 models.

The brace of rear-drive, mid-sized coupes are 1 inch lower. Their wheelbases are stretched by 9 inches, to 113. Interior space, especially in the rear, is improved substantially from 1988.

The two cars undergo their third major restyling since adopting the "aero look" in 1983. They ride on a new platform with separate front and rear subframes, independent rear suspensions and new front suspensions.

Performance versions are the Thunderbird Super Coupe - which replaces last year's Turbo Coupe - and the Cougar XR-7. Both are powered by Ford's first supercharged engine in more than 30 years - and the the first supercharger offered by a U.S. carmaker since Studebaker did in 1964.

Bolted to the 3.8 liter V6, which is standard on all other models, the latest generation supercharger is belt-driven and raises horsepower to 210 at 4,000 rpm by forcing more air into the combustion chambers. Top speed is about 145 mph.

A 4-speed automatic or 5-speed manual transmission is offered. Standard on the Super Coupe and XR-7 are anti-lock disc brakes, automatic suspension control, electronic power steering and performance tires on 16-inch wheels. Options include a compact disc player and anti-theft system.

Air conditioning is standard on all models, which also include the base Thunderbird, Thunderbird LX, and Cougar LS.

Most of Ford's other car lines have minor improvements for 1989. Ford's Probe sports coupe, dubbed a 1989 model, was introduced last May.