Know anyone who seriously thinks the current 911 needs replacing? Probably not. But Porsche thinks otherwise. The 2012 Porsche 911 will be replaced later this year by a car that's as new as its looks are familiar.

It might look nearly identical to the old 997 series, but almost everything about the new 991 series 911 has changed, including the philosophy behind the car itself.

We will know a lot more when we actually drive the car later in the year, but for now, after a day riding shotgun in the new 911 through the mountains of South Africa, it is safe to conclude that this is a 911 like no other we have seen to date.

What Has Porsche Done This Time?

The answer is to start again. You can argue that the changes that turn the 997 into the 991 are just as comprehensive and significant as those that ended the reign of the 993 in 1998. Sure, there is nothing quite so culturally shocking as the abandonment of air cooling for water radiators, but the overall transformation into the 991 is at least as significant.

Perhaps most fundamental is the way the new car is made. Roland Achleitner, the man in charge of reinventing the 911 says, "I am neither an aluminum nor a steel man — I am a correct materials man."

His philosophy explains not only why the bulk of the 991 is now aluminum for lightness where once it was steel, but also why ultrahigh-strength steel has been retained for use in the major crash paths, particularly in the route over the A-pillars and around the passenger safety cell. Had it been built like the 997 the car would now be a minimum of 120 pounds heavier; in fact, it is lighter by a small but still significant (and undisclosed) amount.

The next big change involves the wheelbase. Since its launch in 1963, the 911's short wheelbase has been a defining characteristic of the car much like the flat-6 engine in the trunk.

But now, and for only the fourth time in 48 years, that wheelbase has been extended. By how much we can't say, as our access to the car was made on the condition that we would keep certain details under wraps. We can say that the extra space between the wheels does more than merely provide more legroom in the back; it fundamentally affects the character of the car.

Drivetrain Remains Familiar

The engines are probably the least altered part of the car, but only because the direct-injection flat-6 (unrelated to all previous 911 engines) has only been in production since 2009. Even so, the 3.8-liter engine used in the "S" model gets a useful power gain to 400 horsepower, while the standard motor actually shrinks in size to 3.4 liters but offers 350 hp, 5 more than the old 3.6.

Porsche won't give 0-60-mph times yet, so we'll guess. Figure the base car will get there in around 4.6 seconds and the S in 4.3 seconds, an improvement of 0.1 and 0.2 second respectively. Directing this power to the rear wheels alone (though all-wheel drive is naturally in the pipeline) is Porsche's familiar PDK seven-speed gearbox. Nothing too surprising here, you might think.

That is until we realize that one of the cars charging east from South Africa's Atlantic coast toward the Indian Ocean has a manual version of this transmission. And if you thought a stick-shift PDK was a contradiction in terms, you are not alone. But there it was, complete with three pedals and seven speeds. Porsche hasn't actually said it's going to use this gearbox in production cars, nor did it talk about any alternative, so read into that what you will.

Electric Steering Invades the 911

Not content with changing the way the 911 is built or extending its wheelbase, Porsche has not been afraid to meddle with the 911's most precious possession, one even more key to the car's character than its flat-6 engine. It has replaced the hydraulic power steering used by every 911 since assistance was introduced in 1989, with an electric system.

If this sounds like a minor, backstage detail, it's not. We have yet to drive a car that's been improved by electric steering, and driven plenty that have been ruined by it.

Moreover, Achleitner freely admits that the steering of a 911 is "the most important thing to get right." He says that he spoke to a huge number of suppliers and that ZF got the job because its system is so good, "you would not be able to tell it is electric."