From Aaron Gold,
Your Guide to Cars.
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For 2008, the Cadillac STS gets what industry insiders call a "mid-cycle refresh" with updated styling (including a new chrome grille (link goes to photo) and silly chrome fender vents) and several new features. But the big news is under the hood, where you'll find an updated V6 engine with modern direct-injection technology that promises to make the base-model STS faster and more fuel-efficient than ever. Does it work? And is it enough to keep the STS competitive with its rivals? Read on. $43,355 base, $56,530 as tested, EPA fuel economy estimates 14-17 city, 21-26 highway.

First Glance: Direct injection makes its debut in the STS

Larger photos: Front - rear

Shortly after the Fed passed the new 35 MPG Corporate Average Fuel Economy (CAFE) standard, which requires automakers to start making across-the-board fuel economy increases by 2011, word came that General Motors had cancelled development of a new high-output V8, rumored to replace Cadillac's aging Northstar V8 in 2010.

But after driving the 2008 STS with its new high-tech V6, the idea of a six-cylinder Caddy really doesn't seem that far fetched. The new engine is a direct-injection (DI) version of the 3.6 liter V6 that puts out an impressive 302 horsepower and 272 lb-ft of torque. To put that in perspective, the 4.6 liter Northstar V8, still optional on the STS, tops the new DI V6 by only 18 hp and 43 lb-ft. And that's on premium fuel -- the V6 runs on regular.

The secret is the V6's direct fuel injection system, which sprays gasoline directly into cylinder rather than pre-mixing it with air in the intake manifold. DI allows for much more precise fuel metering, which translates to more power, cleaner emissions, and better fuel economy. Compared to last year's non-DI V6, the new 3.6 makes 47 more horses and 20 more lb-ft, yet EPA fuel economy estimates are higher by 1 MPG. Caddy's DI V6 isn't the first direct-injection engine to hit the market, nor is it the first V6 to crack 300 horsepower. But it does represent a major leap forward for Cadillac and General Motors.

In the Driver's Seat: Great interior, so-so gadgetry

Larger interior photo

I quite liked the STS's cabin with its muted two-tone tan finish and restrained use of wood and brushed metal. The materials aren't quite on par with Mercedes, but the overall effect is nearly as elegant.

The stereo and climate controls, though a bit button-happy, are well marked and fairly easy to learn. Not so the optional navigation system, which is chock full of ambiguous icons. Program an address and the touch-screen presents you with unlabelled pics of a circle and a diamond. Press one and navigation starts; press the other and you have to start all over. It's like road-going three-card Monte. (That said, if you can get it to work, directions are projected onto the windshield via the optional head-up display -- very cool.) And don't bother asking the voice-command system for help: It will tell you that help is not available when the car is moving. Wait -- what? Isn't the whole purpose of a voice-activated system so you can safely use all these gizmos while the car is moving? Luckily, the STS comes standard with OnStar, so you can press a button, talk to a human, and have turn-by-turn directions displayed on the car's stereo.

Other high-tech gizmos include a lane-departure warning system, which beeps at you if the STS starts to drift out of its lane (or if you change lanes without signaling -- thanks, Dad). A blind spot information system displays a small amber light in the side mirror when there's a vehicle just off the STS's rear fenders. Nice idea, but it's no substitute for properly-adjusted mirrors and a quick glance over your shoulder.

On the Road: Engine lives up to its promises, but suspension doesn't

So how powerful is the new V6 engine? Powerful enough that I had to open the hood to make sure someone hadn't snuck in an extra pair of cylinders. The DI V6 really does pull like a V8, but fuel economy is distinctly six-cylinderish: I averaged 19.5 MPG during test week, much better than other 300-horse V6-powered cars I've tested such as the Infiniti G35 and Lexus IS350.

The rear-wheel-drive STS (all-wheel-drive is optional) gets a six-speed automatic transmission with a "sport" program and a manual shifting mode. My test car had a problem with full-throttle downshifts: Flooring the pedal resulted in a pause and then a lurch as the transmission jumped into a lower gear. General Motors automatic transmissions don't usually display such crass behavior, so it's likely there was a mechanical fault with the car I drove.

Unfortunately, the STS' suspension isn't as good as its powertrain. The ride is hard and bumpy, yet the STS doesn't deliver the crisp curvy-road response of a true sports sedan. On twisty, bumpy roads, the STS feels cheap and hollow, more like a $20,000 Chevrolet than a $50,000 BMW.

The STS comes standard with Stabilitrak electronic stability control. New this year is a version that can actually make steering corrections for you. Unfortunately it's only available with the V8, so I wasn't able to try this rather intriguing piece of safety technology.

Journey's End: Great engine just isn't enough

The good news is that the STS proves that real Caddys can make it on six cylinders. The DI V6 is a fantastic engine, delivering the V8-like response American drivers crave with the respectable (if not fantastic) fuel economy we need.

The bad news is that the rest of the STS isn't nearly as good as what's under the hood.

The STS feels to me as if it's trying to be too many things to too many people. It's attempting to combine Japanese gadgetry, German road manners, and traditional American luxury, and it just doesn't work. The gadgets aren't all that intuitive, the handling is sub-par, and the overly firm suspension makes it hard to relax and enjoy the ride. Factor in the STS' mediocre crash test performance and options that can catapult the price well into BMW and Mercedes territory, and it's hard to make an argument in favor of the STS.

If you want a true sports sedan and can do with less room, I'd recommend Caddy's own new-for-2008 CTS or the Infiniti G35. If you need extra space, the BMW 5-series is the way to go. And if luxury is what you're after, check out the Mercedes-Benz E-Class. If you're looking for trouble-free luxury on a budget, it's hard to beat the $35k Lexus ES350. And the upcoming 2009 Lincoln MKS looks promising.

Bottom line: There are several cars that simply do the job better than the STS. The new engine is great and the interior is well done, but those things just aren't enough to make the STS stand out. -- Aaron Gold

Next page: Likes/dislikes, who should buy it, details and specs