So just as the title asks, which is more important to you when it comes to the Buick Regal and the Regal GS - performance or fuel efficiency?
Since I like to sit on the fence for a lot of issues, I'd like to see a mix of both. Though I'm not an engineer, I don't see why there can't be a healthy mix of both performance and fuel efficiency - I don't like the idea of having to sacrifice one for the sake of the other.
There are mods that "beat the system" and others that break the rules. When looking at EPA fuel mileage numbers for a turbocharged car, they look so good because the EPA test cycle never really engages the turbo. Same thing for emissions output. Once its in your hands, you'll have a hard time trying to get the published numbers without Granny driving.
It looks like direct injection is going to break the rules, but only time and personal experience are going to tell.
There was speculation about a "mild hybrid" version early on.
At one time, Jim Frederico, vehicle line executive for the Regal stated, "The Regal can accommodate a number of technologies, including the new BAS system and a plug-in powertrain due at the end of next year."