TOPLESS TWO-TIMER; Summer never felt so good as it will in a 335i Convertible, and winter ain't bad, either.(News)

Byline: MARK VAUGHN

What could be more fun than a 335i? How about a 335i with no roof?

BMW chopped the top off this iconic coupe and replaced it with three concentrically stacking pieces of steel that eventually make their way into the trunk in 22 seconds of holding your finger on a button. That's less time than some of the relationships you'll enjoy once you buy one of these cars.

For those keeping track, this is the fourth BMW 3 Series convertible made since the first one 20 years ago. We remember that one, with its bolt-upright front end and straight-up windshield hacking through the German air like a badly deflating Zeppelin. We drove an original in Deutschland 20 years ago, with its fabric top stowed snugly beneath a hard tonneau cover as the wind tried to rip the shoulder belt and our left shoulder completely out of their sockets. Wind management is much better in this version.

Engineers went for an "open'' feel, but not at the expense of wind management. Indeed, driving the newest 3 Series convertible was a lesson in proper aerodynamics. The new car comes with a massive wind blocker covering the rear seat and holding back much of the roar that would rage against the back of your head, despite the car's relatively short windscreen. With the windows up, you almost don't notice the wind at all, as long as you're not going at more than double-digit speeds.

Yeah, yeah, you say. Quit yappin' about how yer damned pompadour stayed in place, and tell us about structural rigidity.

It is not only structurally sound, but it might just be the stiffest convertible we've ever piloted-no discernible wiggles or shimmies on any of the roads we drove it over in and around Scottsdale, Arizona. It is 50 percent stiffer than the most recent 3 Series convertible, and who knows how much stiffer than that car we drove in the '80s. The technically proficient will appreciate that when you twist the convertible body, it requires 15,000 newton meters of force to deflect it one degree (Newton would have loved this car, and not just because his fancy hairdo would not be ruffled while under way).