2008 Cadillac STS

Cadillacs need V-8s, at least. We know that. Except that GM's most potent V-6 ever, a new direct-injection 3.6-liter, has come along. With its 11.3:1 compression ratio, it has 47 more horses than the 3.6 on which it's based. The 2008 STS V-6 is just 18 horses shy of and 22 pounds trimmer than the STS V-8. Keep the hood shut. No one will know.

Direct injection also gives slightly better fuel mileage and cleans start-up emissions by 25 percent. It's clear the new DOHC V-8 GM is developing for the 2010 STS will have direct injection, possibly making eight cylinders relevant in this car again.

Most direct-injection gas engines start up with a gravelly diesel voice. Not this Cadillac, with fuel-system sound shields and covers to prevent metal-on-metal clatter. The engine remains quiet until you put your foot into it, unleashing a V-6 rumble satisfying enough to make you roll down the windows. The Cadillac is further wrapped in a facelifted STS with a Sixteen concept-inspired nose and has a tastier interior that hides some of the 2007 STS's plasticky parts with supple leather and vinyl and elegant woods and metals.

StabiliTrak 3 will be available for about $1000, with a new active front-steering system, offered at launch only with all-wheel drive. This hyper-power steering feels more natural than BMW's, with none of the linearity problems. An effective blind-spot alert and lane-departure control also will be packaged as a $1000 option.

Cadillac let out only the rear-drive 2008 STS on public roads for initial impressions. Yes, the D.I. V-6 felt like a V-8, although its six-speed automatic hiccupped a few times, either a preproduction issue or lack of break-in miles. The interior still suffers hard black plastic, particularly at the top of the doors, but it's Cadillac's nicest non-v interior until the 2008 CTS arrives. That car gets the same D.I. V-6 with slightly different power and torque numbers due to different intake and exhaust tuning. The kicker is that, with its all-new interior and sheetmetal, the 2008 CTS could render the STS V-6 as superfluous as an STS V-8.