The styling has been likened to a Pontiac Grand Prix, the I-Drive system to your worst computer nightmare. And with the 4^th generation 5 Series selling at a record pace after seven years on the market, you have to give BMW a certain grudging credit for having the guts to make changes this radical in its bread-and-butter sedan. With the 7 Series plying the upper atmosphere of the sports-luxury market, and the more prolific 3 Series still a couple of years away from its next overhaul, the 5 Series stands as the bulwark of BMW’s fortunes.

The changes to the 5 Series are more than skin-deep. The car is larger in every dimension, and now has a rear seat made for adults and a trunk capable of carrying their luggage. Aluminum is the material of choice ahead of the A-pillars, and it is bonded to the steel aft structure with adhesives and self-piercing rivets. Lighter than the model it replaces, the car steers clear of a pure aluminum gambit in favor of one that uses the best materials for the job.

The new 5 also steers clear of the compromises associated with making a sporting sedan more sporting. Things like a harsh ride, jittery handling, road noise intrusion, and at-limit histrionics. This is, in fact, the first case in memory where an optional “sport package” didn’t have me wishing for more compliance. The key is Active Roll Stabilization, a system that uses hydraulic actuators to join each side of the anti-roll bars. In straight-ahead travel, the link is open, which lowers the effective spring rate. Yet, at cornering rates up to 0.80 g, the units lock to hold the body almost flat, with increasing roll as the cornering limit approaches. The package also includes 18-in. run flat performance tires, sport suspension settings, and Active Steering. The latter adds or subtracts steering angle at the road wheels depending on speed and conditions to provide greater agility and comfort.

On the road, the 530i is about as agile as you could desire, surprisingly compliant, and impressively quiet. The structure is supremely solid, feeling as though it was forged from a single piece of metal, then machined to order. It’s not uncommon to drive a vehicle that performs well on a closed circuit, but falls short on the open road where varying terrain and changing conditions prevent a clinical approach to cornering. In these situations, every corner is a surprise, and every mile one that can’t be replicated. You look for how a car responds to commands given with authority, but subject to being countermanded at a moment’s notice. You push the car hard, yet leave room for escape. And you learn – quickly – whether or not you can trust it to respond appropriately. In this the 5 Series excels, pointing into corners crisply and with a minimum of roll, swallowing irregularities in the road surface, and leaning gently on its outside rear wheel in anticipation of the coming acceleration. And – should you get it wrong – hauling down hard under braking with nary a squirm or shudder.

You can’t hide a basic inadequacy in a vehicle’s dynamic package with techno-trickery. No matter how good the software engineer or how adept the electronics, if the basic engineering and dynamic package isn’t strong, they won’t help. If these elements are right, the electronics become a seamless addition. And on the new 5 Series, they are just that – seamless. It is why this car will appeal to current and potential owners, despite some uneven styling (including Subaru Impreza-like tail lights) and an I-Drive system that’s still more difficult to use than necessary.