BMW is riding high after its best sales year in the United States. Sales rose 12 percent in 2012 compared with the previous year. Smaller vehicles in the lineup spurred the most growth: Sales of the 1-Series jumped 29 percent; the all-new 3-Series sedan drew 22 percent more business for the brand; and X3 sales climbed 27 percent.

As the German automaker gets closer to launching the first in its line of revolutionary new carbon-fiber-bodied electric vehicles toward the end of this year, it continues to swiftly roll out new and updated products, as evidenced by the four new models shown at the 2013 North American International Auto Show in Detroit.

TOP STORIES FROM THE DETROIT AUTO SHOW:

BMW Concept 4-Series Coupe

What is it? A preview of the 3-Series coupe's replacement. It will share underpinnings of the 3-Series sedan that debuted last year.

What's hot? The long, low, wide proportions and the sleek styling details make this 2-door different enough from the 3-Series sedan that BMW has decided to change its name to 4-Series.

The difference is most striking from the rear view, where the bulging fenders, sloping back window and slim, L-shaped taillights create a unique look. The bumpers have also been changed from those of the sedan. Satin-finish aluminum trim highlights larger air vents. Clever use of aerodynamic features that pull air into the bumpers and around the wheel wells negates the need for unsightly splitters and spoilers and keeps the overall design uncluttered.

The cabin is covered in soft brown leather that was made with an environmentally friendly tanning process. Hand-braided leather stitching is a unique touch that covers even the cupholders on the center console.

What's not? Yet another numerical model designation to keep track of in BMW's already-cryptic vehicle nomenclature.

How much and when? A production version of the 4-Series coupe is expected to launch later this year.

MSN Autos' verdict? It's sexy — much more so than the outgoing model. BMW has a rich heritage of making desirable coupes with even-numbered model designations, such as the 6-Series and 8-Series. This new one only deepens the mystique of that tradition. We can't wait to drive one.

2014 BMW 320i

What is it? A new, more affordable version of BMW's 3-Series sedan.

What's hot? BMW is spreading the sport-sedan love for more people to enjoy. The 320i becomes the least expensive 3-Series version, with a less powerful turbocharged 4-cylinder engine producing 180 horsepower. It will be available as a sedan with rear- or all-wheel drive. A 6-speed manual transmission is standard, and an 8-speed automatic is optional. Although it won't offer as many upgrades and options as others in the 3-Series line, it will by no means be Spartan, BMW says. Unique wheels and one exhaust pipe instead of two will distinguish it from other 3-Series vehicles. Bringing back the 320i name pays homage to the very first 3-Series ever sold in the United States back in the '70s, and we like that, too.

What's not? Less horsepower is never good for enthusiasts like us. But we understand that compromises are required to bring a lower price.

How much and when? The 320i will go on sale in the spring and have a base price of $32,550.

MSN Autos' verdict? We like the idea of BMW making its stellar 3-Series more affordable so that more people can enjoy its wonderful driving dynamics. We hope the less potent engine won't make it feel lethargic.

2014 BMW M6 Gran Coupe

What is it? A 4-door version of the M6 coupe.

What's hot? It slots perfectly between the M6 coupe and M5 sedan and is perhaps the ideal package for those who want the convenience of four doors, but the lower center of gravity and sexier looks of a 2-door. Compared with the M6 coupe, it has an additional 4.45 inches between the front and rear wheels. BMW says the seating capacity is "four plus one," meaning that four adults should fit comfortably and that a fifth passenger would able to squeeze into the rear center seat if need be.

All of the mechanicals are identical to those in the M6 coupe. The 4.4-liter 560-horsepower twin-turbo V8 is the most powerful engine ever used in a BMW M production car. A 7-speed dual-clutch gearbox is the only transmission offered. Zero to 60 mph takes 4.1 seconds. Top speed is limited 155 mph.

What's not? Calling it a coupe when it has four doors. It's nothing more than a marketing gimmick that more and more car companies are using.

How much and when? It will come out this summer; final specs and pricing to be announced.

MSN Autos' verdict: The lower center of gravity of the M6 coupe makes a noticeable difference in its driving dynamics when compared with the M5 sedan. The new M6 Gran Coupe is the ticket for those who want a usable back seat and four doors, but don't want to compromise performance. It would definitely be our choice of the three.

2014 BMW Z4 Roadster

What is it? A mildly updated version of BMW's roadster.

What's hot? Everything we love about the Z4 remains unchanged, including its awesome turbocharged 4- and 6-cylinder engines. A BMW spokesman said various subtle changes to the suspension and chassis improve the car's ride and handling. Like before, there are three versions of the roadster: the xDrive28i with a 240-horsepower 4-cylinder, the xDrive35i with a 300-horsepower 6-cylinder and the xDrive35is with 335 horsepower. Fuel economy remains impressive at an estimated 19 to 26 mpg overall, depending on the engine.

Changes to the exterior and interior are so subtle they're hard to distinguish. The folding hardtop can now be raised and lowered at speeds of up to 25 mph, and it can be ordered in two contrast colors, black and silver. A new Hyper Orange trim package offers a vibrant color choice with faux-suede Alcantara interior appointments.

What's not? No high-performance M variant yet. Come on BMW, we're waiting.

How much and when? The new Z4 will hit showrooms in the spring for about the same price as last year's model.

MSN Autos' verdict: If you already have a Z4 roadster, there's no need to rush out and replace it with this new version. Changes are purely cosmetic. Thankfully, BMW did not mess with the successful formula it concocted in the first place.

Matthew de Paula wanted to be an automotive journalist ever since reading his first car magazine in grade school. After a brief stint writing about finance, he helped launch ForbesAutos.com and became the site's editor in 2006. Matthew now freelances for various outlets.