By Jim Meachen and Ted Biederman

The car formerly known as the 3-Series coupe has been reinvented and becomes the first in a new BMW lineup with a 4-Series designation, a reclassification designed to elevate the coupe into something just a bit sportier, slightly larger and with more feature content than the 3-Series. It also comes with a price starting about $2,000 higher.

While the new 4-Series shares the same platform with the sixth-generation 3-Series it's stretched in both width and wheelbase with a wider track lending to sportier handling and more road grip.

A sportier driving demeanor aside, BMW carried over the 3-Series powertrain lineup that includes a 2.0-liter inline 4-cylinder good for 240 horsepower (428i), and the muscular turbocharged inline 6 making 300 horsepower (435i). All-wheel drive is available with both engines as a $2,000 option as is the choice of a six-speed manual transmission or an eight-speed automatic with paddle shifters.

We drove the 435i for a week and discovered what we had expected — a personal-sized coupe with dynamic handling, impeccable road manners, thrilling performance and decent ride quality. The new coupe proved an extraordinarily balanced, confidence-inspiring machine on our usual twisting rural-road test route. In short, it was hoot to drive as hard and fast as individual driving skills allow.

In the need for speed category, the turbocharged six is the engine of choice with a 0-to-60 time in the upper reaches of four seconds and a quarter mile time around 13.3 seconds at over 100 mph. The eight-speed shifter is smooth and precise and can be managed manually with paddle shifters. Our test coupe came with the M Sport trim, which added such things as adaptive M suspension and four driving dynamics choices — Eco Pro, Comfort, Sport and Sport Plus.

We mostly drove at the extremes, Eco Pro and Sport Plus, and found a slightly dulled throttle response and softened ride in Eco, which presumably will yield better gas mileage. None-the-less, we figure most people who have shelled out more than 50 grand for a 300-horsepower sports coupe, will ignore the Eco and do what we did — keep the Bimmer humming along as it was designed to do in Sport Plus mode.

While we adore BMW's twin-turbo six, don't discount the less expensive 428i four-cylinder model (that we also drove), which offers the handling traits of the six and enough performance to keep driving life interesting, measured at 5.4 seconds from 0-to-60 and 13.8 seconds at 98.7 mph in the quarter mile.

The one downside to this otherwise satisfying performance narrative is BMW's rather abrupt engine stop-start feature, which cuts the engine off when stopped as a gas savings technique and then starts it back when the brake pedal is released. For those who find it annoying, it can be manually disabled.

While styling differences are apparent on the exterior – for the time being the 4-Series is available in coupe and convertible body styles – once behind the wheel it's nearly impossible to distinguish the new coupe from the 3-Series sedan. And that's a good thing because the cabin features a stylish, sophisticated design with premium materials. The 4-Series carries on with the now familiar iDrive system, which has become less complex and more intuitive over the last decade. The system is relatively easy to use with clear, straight-forward menus, neat graphics and quick operating times.

We found the M Sport package seats offered ample lateral support even for our spreading bodies thanks to adjustable side bolsters. Although we didn't spend more than a couple hours at a time on the road, we figure seat comfort for long hauls should be fatigue free. Back seat leg and head room afforded by the 4-Series was a pleasant surprise, more than adequate for two adults.

There's a wide range of prices depending on engine size and trim level starting at $41,425 for the 428i (ours listed at $47,125) and $46,925 for the 435i. Two of the most sought-after packages in addition to the aforementioned M Sport will be Premium ($2,200), which brings keyless entry and ignition, satellite radio and leather upholstery; and Technology ($3,150), which adds a higher-resolution 8.8-inch display screen, navigation, head-up display and a suite of connective apps for iPhone and Android devices including Pandora, Stitcher and Facebook.

Our 435i test car with M Sport trim with special forged aluminum 19-inch sport wheels and several other option packages carried a bottom line of $57,225.

The Ultimate Driving Machine has never been as appealing — or expensive — in compact form as with this newest numbering designation.

Essentials
Base price: $41,425; as driven, $57,225
Engine: 3.0-liter inline turbocharged six
Horsepower: 300 @ 5,800 rpm
Torque: 295 foot-pounds @ 1,300 rpm
Drive: rear wheel
Transmission: 8-speed automatic
Seating: 2/2
Wheelbase: 110.6 inches
Length: 182.6 inches
Curb weight: 3,550 pounds
Turning circle: 37.1 feet
Luggage capacity: 15.7 cubic feet
Fuel capacity: 15.8 gallons (premium)
EPA rating: 33 highway, 23 city
0-60: 4.9 seconds (estimated)
Also consider: Mercedes C-Class Coupe, Audi A5, Infiniti Q60 coupe

The Good
• Powerful and fuel-efficient engines
• Upscale interior
• Adult rear seating
• Impeccable handling traits

The Bad
• Intrusive auto stop-start system

The Ugly
• Options are desirable, but pricey