The 2014 Mini Cooper and Mini Cooper S. Photo credit: BMW Group

When cheeky British brand Mini unveiled its all-new 2014 Mini Cooper at last week's Los Angeles Auto Show, few were surprised to see that the new Mini looked an awful lot like the old one. 

It has been changed, but the visual differences are subtle. It's a little more modern looking, a bit sleeker in front. But nobody will mistake the new car for anything but a Mini. 

The differences under the skin are more significant, though. And that's where we start to see how crucial the 2014 Mini Cooper is to Mini's corporate parent, BMW (BAMXF -3.91%).  

This new Mini is probably the first of several
Properly speaking, the car that Mini showed off last week is called the 2014 Mini Cooper Hardtop. The "Hardtop" moniker distinguishes this -- the basic 2014 Mini Cooper -- from all of the variants that the revived Mini has spawned over the last 13 or so years. 

It's a long list. There's the Convertible, the Paceman, which is a crossover SUV-ish variant, the Clubman, which has a longer wheelbase, the Countryman, which is a bigger Paceman, the two-seater Coupe, and the Coupe's convertible sibling, the Roadster. 

Add in an assortment of higher-performance versions, and it's an elaborate -- and somewhat confusing -- lineup.

Like its exterior, the 2014 Mini Cooper's interior is new and different, but still very familiar. Photo credit: BMW Group

The Hardtop is the only all-new Mini we've seen so far, but it's fair to say that all-new versions of the other variants are probably on the way. 

There might even be a new variant: Mini executives have recently hinted that they think there's room for one more Mini model in that crowded little lineup. Electric and plug-in hybrid variants of some or all of those new Mini Coopers are also possible.

The new Mini's cousins: A new line of front-wheel-drive BMWs
All of those 2014 Mini Coopers will be built on a new architecture, one that will be shared with a series of small new front-wheel-drive BMWs. 

For some enthusiasts, "front-wheel-drive BMW" sounds like sacrilege. BMW built its reputation on rear-wheel-drive sedans that combined day-to-day practicality with superb handling.

But BMW sees an opportunity to push into more affordable segments, and to share costs with Mini, whose little cars have been front-wheel-drive all along.

The first BMW on the new platform is being called the "Active Tourer". It's a small crossover that will arrive here in the U.S. in early 2015.

But then comes the change that will ruffle enthusiasts' feathers: The small 1-Series BMWs -- which are currently rear-wheel-drive -- will move to the new front-drive platform starting in the 2017 model year. 

It's not impossible that they'll do well. Daimler's (MBGY.Y 0.15%) Mercedes-Benz brand has seen big sales of its new front-wheel-drive CLA sedan. A front-wheel-drive BMW that offers the BMW brand's cachet and experience at a lower price point could work out well.

At least, that's what BMW is clearly hoping. It's a gamble. But the 2014 Mini Cooper should help make it a much safer bet.

Why this new Mini Cooper is crucial for BMW
The 2014 Mini Cooper will also share its engines with those new BMWs. There are two, both brand-new, and both turbocharged: a 1.5-liter three-cylinder making 134 horsepower, and a two-liter four-cylinder that makes 189 horsepower. The  two-liter is standard in the 2014 Mini Cooper S.

Those engines come with a choice of two six-speed transmissions, a manual and an automatic. Both transmissions are brand-new designs as well.

If you're thinking that an all-new platform with two all-new engines and transmissions represents a significant investment on BMW's part, you're right. It's a key part of a major new-product push that is expected to cost BMW big over the next several years. 

And that's why the new 2014 Mini Cooper Hardtop, and all of the variations that will surely follow, are crucial to BMW. 

BMW sells close to 25,000 Minis around the world every month. For a luxury-car maker like BMW, those are big sales volumes. 

But the company needs those sales volumes to make this new platform worthwhile. BMW shareholders have to hope that the new 2014 Mini Cooper continues to build on the old Mini's success.