With strawberry frosted doughnut in hand, I headed to the far left side of the Lars Anderson Auto Museum in Brookline last Friday, where several dozen auto writers and PR heads gathered for a drive of exotic proportions: a romp to Kennebunkport and back to test 2009's latest convertibles.

There was nothing shabby about the middle and right sides — Corvette, Phantom Drophead, Viper, two Z4s, among others — but over here were three machines touted in $1,000-per-day enthusiast drives, fender-to-fender: a $146,000 SL63 AMG, $200,000 Aston Martin DB9 Volante, and the knight-worthy $400,000 Bentley Azure T. I left the museum in a $50,000 Infiniti G37 Convertible — not a bad starter by any consideration.

Infiniti did a commendable job cutting the roof off the G37 (and creating a new one). Its rear haunches are appropriately flared, and the shoulder line stays low and tight like on the coupe. Trunk space is limited to crushable items only; a thin fabric flap separates the tiny cargo hold from the massive folding roof. Day trippers wonât mind, and will like how pleasant the G37 is at a highway cruise, with minimal wind buffeting and surprising audio clarity from the Bose speakers (with clever tweeters mounted on either side of both front headrests). I didnât pay much else attention to the G37 as I did the matte white SL63 AMG trailing behind me. At a rest stop near the New Hampshire border on I-95, I bolted toward the Benzâs driver to beg for the keys in exchange for mine. Incredibly, he accepted.

Now the MSRP has nearly tripled. Mercedes freshened up the SL for 2009, tweaking the front end for a more sinister appearance and throwing in a brand new AMG-tuned 6.2 liter V-8 good for 518 horsepower. From the ducted carbon fiber valence under the bumper and subtle lip spoiler above, itâs clear this SL isnât content with boulevard cruiser status. The steering wheel is squared-off at the bottom, just like on the Lamborghini Gallardo, and the cockpit is serious business with its dark chocolate leather, steering wheel paddles and several buttons and knobs for extracting maximum volume from the quad tailpipes.

My co-pilot Chris Naughton, Hondaâs Northeast PR manager, plugs in his iPod. But Michael McDonald is soon drowned out by the AMGâs brutal torque as weâre followed by the DB9 and hairy-chested Viper. As I merge to the far left lane, Iâm not sure whatâs crazier â being passed at 80 miles per hour by a Viper with cameras suctioned onto its windshield, or my accidental engaging of the cruise control stalk as Iâm reaching for the turn signals.

Itâs incredibly easy to reach incarcerating speeds in these cars, and soon weâve all settled down into a swift cruise. The SL63 coddles but demands subtle inputs. The steering rack is quick, and throaty downshifts in S+ mode send your head forward. While the brake pedal was a touch soft in initial travel, the big rotors delivered linear, smooth performance. After a jaunt in the SL63, itâs plain frightening to think of the twin-turbo V-12 SL65 AMG, and hard to justify that carâs equivalent premium of a G37 Convertible. The SL63âs delicate balance, incredibly responsive 7-speed automatic and muscle car soundtrack make it the marqueâs most desirable car, at least until the SLS arrives.

When we reach the Maine border at another rest stop, itâs time again to swap keys. A group of young men walking from the bathrooms peep at us with point-and-shoot cameras, and donât move until weâve figured out how to start the Aston Martin and exit out of sight. Itâs not the most intuitive push-button start. After popping out several times, we realized the key fob needed to be pushed and held into its center dash slot for at least two seconds. The fob, capped with a clear glass-like enclosure, blends into the dash so well that a few drivers, forgetting to take out the key, thought they had lost it altogether.

But once started and past the goofy P-R-N-D buttons spanning either side of the key slot (our own John Paul likened it to a 1962 Chrysler), the Aston delivered butter-smooth shifts from its paddle-shifted 6-speed automatic, no matter that the tachometer was spinning counter-clockwise. The DB9âs mission is quick speed without making a scene, unlike the raucous SL63. That means a very hushed exhaust tone at city speeds, which caused me to press the âNâ button to light up Kennebunkport with some proper noise from the 6.0 liter, 470 horsepower V-12. On the highway, acceleration isnât as violent as in the Benz, nor as visceral as the half-price Jaguar XKR Convertible, but the speed comes along just as easily, along with a racket of wind noise.

The other exotics in our fleet, however, canât touch the DB9 on design. The way the doors swivel upwards several degrees, uncovering even more hand-stitched leather along the dashboardâs hidden sides, is just one treat. The arching single piece of wood (endangered and from Africa, hopefully) is stunning, as is the jewel-like design of the instrumentation and delectable 20-spoke wheels accenting a clean-cut body profile. Its performance is impressive, but as a whole the DB9 is too sedated. For pure beauty, the Aston has no equal.

Itâs time to go ultra-snotty on the way back. Automobile Magazineâs Ezra Dyer has just left our surfside lunch spot, the Colony Hotel, in the back of the Rolls-Royce Phantom Drophead. So I head to the back of the Bentley Azure T, which aside from the Phantom (and perhaps the Continental GTC) is the only convertible on the market that can actually fit four actual adults. Legroom is generous, and the rear armrest easily holds small items like a digital camera snugly in place. Red leather covers everything, a perfect contrast to the layers and layers of silver paint on this Old World convertible.

The incredulous stares from passersby are as intense as the sun as Keith Griffin of About.com takes the helm through Kennebunkport. Sitting in the Azure unveils my inner New England snob, and before I know it my scalp is flat on the plush headrest, my right arm hanging off the Bentleyâs flanks, and all of a sudden Iâve welded an iPhone and a popped collar. And Iâm yawning, because the Azure is the worldâs best mattress.

Soon Keith and I trade places, and heâs snoring in the front seat even in stop-and-go traffic on I-95 south. You canât feel anything from the Azureâs suspension â even the worst of ruts donât reach the cabin or upset its occupants. Braking and accelerating are akin to slathering whipped butter on a bagel. Passengers could assume the Azure isnât built to hustle â itâs nearly three tons and the tachometerâs 500 r.p.m increments look straight off a bus â but when the driver leans on the gas, everyone gets thrown back by the V-8âs colossal 738 pound-feet of torque, enough to rush the Azure to 60 miles per hour in 5.2 seconds. Itâs an effortless endeavor, and a very warped take on physics. But when youâre piloting a convertible worth the value of, say, a few dozen cars rushing past in the opposing highway lane, itâs entirely reasonable.

The dayâs winner was the Mercedes SL63 AMG. It doesnât have the jaw-dropping presence of the Aston or Bentley, but offers the best combination of supermodel looks, supercar sound and speed, and a somewhat attainable price. Even if most people canât tell the difference between SL trim levels, the AMGâs lucky driver wonât ever forget.