Until recently, the BMW 4 Series was a sporty,  two-door rendition of the compact 3 Series sedan.

(I mean, look at the specs. The 3 and 4 cars have identical lengths, wheelbases, and rear tracks. Their front tracks and vehicle widths are within a half-inch of each other.)

The two-door nature of the 3 car-derived 4 Series, which includes a coupe and the retractable hardtop I just tested, was expanded to include a model called the Gran Coupe. The latter isn't really coupe since it has four doors, but who's counting entrances? What the Bimmer marketing meisters are counting is the number of Gran Coupes idling out the door. Indeed, they've more than doubled 4 Series sales.

The coupes and Gran Coupes are handsome and athletic Teutons, but I prefer the convertible I played with. I like to drop the top, even in cool climes, and feel the breeze on my white-thatched roof.

Like its fixed-roof brethren, the convertible was refreshed for 2018. But since it was pretty to begin with, a good deal of the 2500's new parts were performance-minded. The aesthetic changes were pretty subtle. Indeed, you need a doctorate in Bimmerology to tell a 2018 from a 2017.

The styling changes include new wheels and front and rear lighting. The front and rear fascias are also fresh on all but the higher-performance M models.

The test car's interior was very attractive, made lovelier by its Cognac leather seats, a $1,550 option. That sort of extra cost item was typical of the tester. While the car checked all the usual luxury boxes in its $51,450 base form, what made it really luxurious was a series of costly options that raised the ante to $63,310.

But hey, let's not make light of this car's German generosity. As the Monroney sticker informed me, BMW provides the AC refrigerant at no extra charge.

Performance enhancements include faster-acting antilock brake actuators that affect modest improvements in braking precision and stopping distance. The steering was revised to improve response.

The fixed roof models also get stiffer anti-roll bars for better cornering and new damping technology that enhances body motion control.

While the convertible is short-changed when it comes to these standard suspension improvements, the tester did have the adaptive suspension that was part of the $2,300 M Sport Package.

The bottom line was composed, precise handling that was simply joyful. While the ride was predictably firm, especially in the "Sport" driving mode, it was supple enough as to not beat you up on the bumps.

2018 BMW 4 Series Coupe (European model)
Courtesy of BMW
2018 BMW 4 Series Coupe (European model)

The 4 Series cars are available with two turbocharged engines. The 440i is fitted with a three-liter inline six that develops 320 horsepower, while the 430 model I drove is motivated by a two-liter, 248-horse four. Both engines can be buttoned to an eight-speed automatic gearbox or a six-speed manual in the fixed-roof models. The convertible comes only with the automatic.

The six is a rocket, getting from zero to 60 in a follicle under five seconds. The four does that calisthenic in a little under seven.

The testers' four-banger, mated to the smooth automatic, proved lively enough to be fun —and made the 430i convertible $7,050 cheaper than the six-cylinder 440i convertible. The engine was civil enough under normal driving conditions, but did get a tad raucous when flogged.

It also earned EPA mileage ratings of 24 city and 34 highway, quite presentable numbers for a performance-oriented ride.

BMW calls this engine a "TwinPower Turbo," but don't assume that signifies two turbochargers at work. Rather, it uses a single turbo with a "twin-scroll" design. The latter produces more power and less torque lag than a conventional single-scroll turbo.

2018 BMW  430i Convertible

Base price: $51,450.
As tested: $63,310.
Standard equipment: two-liter engine, eight-speed automatic gearbox, rear-drive and an ample array of  stocking stuffers ranging from heated, 10-way power front seats to run-flat performance tires. (BMW uses big stockings.)
Options: Goodies running the gamut from a heated wheel (l$190)  to a neck warmer ($500).
Fuel economy: 24 mpg city and 34 highway.
Engine performance: Lively.
Handling: Fun, fun, fun 'til daddy takes the B-word away.
Ride comfort: Acceptable.Styling: Comely.
Warranty: Four years/50,000 miles bumper to bumper.
Four Bens: Excellent