"Don't park it under oak or pine trees. We don't want sap dripping onto it. And be very, very careful with this one. It's almost $100,000," the delivery representative said of the car I was about to receive.

 

"It" was a 2008 Mercedes-Benz CLK63 AMG High Performance Cabriolet. And it sells for $98,245.

The car doesn't shout its worth in a flashy way, yet a brief test drive confirms why it costs so much. The tipoff is the AMG part of its name. AMG is a division that takes production cars from Mercedes-Benz and turns them into executive hot rods.

Under the hood of this CLK63 is a big 6.2-liter, 32-valve V8 that is hand-built. It produces 475 horsepower at 6,800 rpm. Its torque is a stump-pulling 465 foot-pounds at 5,200 rpm. This is a very powerful car.

Now, there are few places where such power can be tested on today's bumper-to-bumper roads. So any "test" will likely be short. No problem. Jumping from zero to 60 in under five seconds is something of an adrenaline rush.

I expected the rush.

I got more.

Understand that this is not a big car. Not heavy. So it can make maximum use of its horsepower (power is realized best when it has the least work to do; big horsepower + light car = very fast because there's not much weight to put in motion).

On a deserted stretch of road, I pressed the accelerator to the floorboard while rolling at about 5 mph. The AMG hesitated the briefest of split seconds before turning loose its rush of power. I was pinned back in the driver's seat. Really pinned. I felt a gear shift from the 7-speed automatic transmission and glanced quickly at a speedometer needle rapidly sweeping clockwise. Then—in a very rare instance for me—I felt the blood draining from my head. A kind of blurry dimness began.

G force.

It's what Blue Angels pilots experience in their jet fighters as they accelerate, make tight turns or pull out of a dive. Indeed, the force overcomes the strength of the heart to pump blood to the brain. If continued, it results in a blackout. Whether in a jet or a fast vehicle, the result is often fatal.

I backed off the accelerator and pulled onto a side road. Blinked. Took some deep breaths.

Whoa. How did that happen? I've driven Dodge Vipers and turbocharged Porsches under all-out acceleration and never had the blood drain away like that. What happened? I decided it was a freak occurrence. I'd try again.

I turned the Mercedes back onto the empty stretch of road and again slammed the accelerator as my turn straightened out. The car blasted forward, seemingly outracing my brain's attempt to keep up with my place in space.

And I felt that dimness start yet again.

This car is so blazingly quick that it could get me killed, I concluded. I also concluded I would not apply to become a Blue Angel. At least I was thinking straight as I slowly drove home.

This is not the only way the CLK63 is excessive, however. It is, indeed, the fastest four-passenger car I've ever driven. But a buyer will pay for that in several ways. After the sticker price shock, take a look at the fuel efficiency rating. That likely won't deter the speed buff with $100,000 to spend on a mid-size car, but the EPA estimates are 12 in the city and 18 on the highway. You'll always pay for premium gasoline, too. I averaged 14 mpg in test week.

Those figures are so bad, even in comparison to other speedsters, that the federal government tacks on a whopping $2,600 gas guzzler tax.

Green, this car is not.

Mercedes-Benz must have read my mind, because the next M-B I was sent was the 2008 R320 CDI. The "D" stands for diesel. And this one is the polar opposite of the carefree convertible.

The R320 CDI is a family hauler with three rows of seats, every imaginable luxury option, a monstrous front row-to-rear row sunroof and two TV sets built into the front seat head restraints. Under its hood is a three-liter V6 diesel engine that makes 215 horsepower. That's really enough for most driving needs. This one returns 18 mpg city and 24 mpg highway. In mixed driving, I averaged 22.5 mpg.

Think of it as a huge luxovan that might be called planet-friendly.

The sticker begins at $45,400 but the final cost of our tester was $65,275.

Around town, both of these models were pleasant. The convertible has a sportier suspension, which means those inside will feel but never be irritated by irregularities in the road surface. Those in the CDI can hear the diesel engine's telltale clatter. Again, it's not annoying, just a fact.

Each had the full complement of navigation systems, rear cameras, voice-controlled devices, special headlights, multiple air bags, etc.

"What'd you think?" the delivery guy asked when he came for the convertible.

"First car that almost made me black out during acceleration," I replied honestly.

He laughed. "It's quick. Maybe you'll like this one better," he said of the diesel van. He knows I like diesel cars and own one.

"Looks like a suppository," I said.

"You're not going to print that, are you?"

I smiled.