The new BMW 4 Series Convertible will have a starting price of $49,675 for the basic 428i model.
The 435i model will cost from $55,825, and both cars will be available in showrooms by early 2014.
The 4 Series is larger and wider than the outgoing 3 Series version. The 428i will feature a 240hp turbocharged 2.0-liter l4 engine producing 255lb/ft of torque. It will be able to do 0-60mph in around 6.2 seconds.
Meanwhile, the 435i has a 3.0liter turbocharged l6 producing 300hp and 300lb/ft of torque which can do 0-60mph in 5.5seconds. Both have an electrically limited top speed of 155mph.
They both have an eight-speed automatic transmission. The 428i will be available as both a rear-wheel drive and and all-wheel drive, whereas the 435i will only be rear-wheel drive.
The two models are each around $800 more than their 3 Series predecessors.
The hardtop is said to have improved retractable roof design and build, helping to keep the ride quiet on the road and providing comfort in all weather conditions.
The front seats can be equipped with neck warmers for cold winter drives. They adjust temperature automatically in relation to the outside temperature and how fast the car is travelling, after it calculates the wind chill factor.
Sport seats with recessed head restrains can be fitted as an option, and dour different specifications of the car are available: standard, Sport Line, Luxury Line and M Sport.
The 4 Series also has lower suspension, which provides a sportier drive. Fuel efficiency is said to be good.
When the top is up, the luggage compartment has a volume of 13 cubic feet (370 liters), 0.7 cubic feet (20 liters) more than the outgoing 3 Series Convertible. When the three-piece top is down it is stored in the trunk.
The Sport Line adds sport suspension, plus a sportier look including 18 inch or optional 19inch ligh-alloy wheels (only on the 435i).
The Luxury Line has high-gloss chrome touches to make the car look more elegant.
And the top-of-the-range M Sport includes several extra body components: larger air intakes, rear bumper diffuser, and side skirts, plus improved suspension and brakes.