About two years ago, under the influence of an eager Tesla representative, I briefly considered trading in my trusty 2013 Tesla Model S 85 for a new Model S 90D.

But after a 24-hour test drive, the advantages of the 90D—40 miles more range, all-wheel drive, and Autopilot 1.0—didn’t seem to justify the $40,000 cost of stepping up to Tesla’s latest and greatest.

“Not a chance,” I wrote at the time. “I’m good with the old car.”

That was then. This is now.

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Some things changed in the meantime.

My financial outlook improved: I had a very good year for one of my investments, and I have only one more year of college tuition for my daughter left.

I turned 70 years old. For decades I’ve been saving and investing so I’d have money to spend in my old age. And suddenly, officially, here it is.

I recently suffered a retinal detachment, an abrupt reminder that stuff happens. Tomorrow I could be blind—or dead.

Tesla introduced the Model S 100D, with all the benefits of the 90D, plus an EPA range of 335 miles—a full 90 miles more than my old 85.

Tesla introduced Autopilot 2.0, with the expectation of fully autonomous driving capability within a couple of years.

The 100D now looked pretty enticing.

2017 Tesla Model S 100D [photo: David Noland, owner]

Beyond the strictly visceral lures—better acceleration, the cool new thing—there were some compelling practical advantages as well.

All-wheel drive would clearly help during my winters in New York's Hudson Valley. An extra 90 miles of range would ease my annual cross-country drive to California.

And the potential for full autonomy in a couple of years would come just when my own driving skills and confidence might begin to fade.

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And so, last April, I pulled the trigger on a new 100D.

With metallic paint, Silver Cyclone 19-inch wheels, premium seats, and air suspension—but no Autopilot—the MSRP came to $101,800. With my current-owner discount and federal and state tax credits, the effective post-incentive total came to $91,300.

Tesla gave me $33,250 trade-in on my old car, so my net cost was $58,050. (I know, I know. What can I say? Life is short, and you can’t take it with you.)

2017 Tesla Model S 100D [photo: David Noland, owner]

The car arrived in late June. After 3,000 miles, I’m pleased with my new baby so far—even though I’ve yet to enjoy any of the 100D’s major advantages over my old car: the all-wheel drive, 335-mile range, or autonomous driving.

Here are some of the smaller advantages I’ve noticed:

Better seats: From the moment I first got into the car to drive it home from the Tesla delivery center, I felt the extra support along the thighs and lower back.

Better acceleration: On paper, the 100D’s 0-60 time of 4.1 seconds is markedly faster than my old 85’s 5.2 seconds. I can definitely feel the difference.

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Faster Supercharging: Despite the larger battery capacity, the 100D takes less time to supercharge.

Although peak charge rate is about the same as the 85—115 kW—the 100-kWh battery maintains a much higher charge rate as the battery fills up. At 50-percent state of charge, the 100D will still charge at 100kW—a huge improvement over the 85.

However, I’ve noticed the 100-kWh battery seems very sensitive to temperature. On very hot days, or on cool days if the battery isn’t fully warmed up, charge rate falls off more rapidly than I recall it doing with the 85.

2017 Tesla Model S 100D [photo: David Noland, owner]

Better efficiency: In summer weather, my 85 averaged 290-300 watt-hours per mile energy consumption. So far, the 100D seems to be matching that figure. For a car that’s 100 pounds heavier, has better acceleration, and all-wheel drive, that’s pretty good.

But the EPA says the 100D should be 15 percent more efficient than my old 85 (102MPGe vs. 89 MPGe.) By that yardstick, the 100D should be showing me 250-260 Wh/mi. Not even close.

Similarly, every other dual-motor Tesla I’ve driven, even with all their gaudy EPA efficiency numbers, has failed to beat the real-world efficiency of the rear-drive cars. Something is clearly awry with those EPA efficiency numbers. This puzzle has baffled me for years.

I’m also curious to see how cold temperatures will affect the 100D’s efficiency. On the few cool days so far, Wh/mi readings seem to be edging up more than they did in the 85. We’ll see as temps drop further in the coming months.

*Better rearview camera: Sharper resolution, better color, wider field of view. Nice.

*Stronger regenerative braking: Although the power meter shows the same 60-kW max regen, it feels stronger to me. (With two motors to absorb the power, it makes sense.)

But the 100D’s regen is more sensitive to the cold than my 85’s. On a recent morning I found the regen frustratingly limited to 40kW with the temp at 62 degrees. How bad will it be at 15 degrees?

2017 Tesla Model S

*Center console: A nice addition. The old 85 had a flat floor with just a couple of low rails to keep stuff from sliding around.

*Better windshield wipers: My old 85 had supposedly “smart” wipers whose two intermittent modes were controlled by an automatic rain sensor. A more accurate name for the two modes would have been Dumb and Dumber; they were virtually useless.

The 100D has old-fashioned manual intermittent modes based on time intervals. Way better.

*Better windshield washer: Instead of the narrow high-speed jets of my 85, the 100D has a wide, gentle spray. Again, way better.

*Walk-away locking: My old 85, which I ordered without the tech package, had to be actively locked via the key fob (What a freakin’ nightmare!)

The new one locks itself when I walk away with the fob, and then unlocks and presents the door handles automatically when I return. I’m ashamed to admit how much I like this feature.

*Proximity warnings: Although the constant beeping from the ultrasonic sensors during tight maneuvers can be annoying, they accomplish their purpose.

2017 Tesla Model S 100D [photo: David Noland, owner]

Not everything about the 100D is better than the old 85, however. Among the downgrades:

*Smaller front trunk: Because of the second motor up front, the front trunk (“frunk”) is much smaller than my old 85’s. We’ll see how much I can stuff in it for my annual winter drive to California.

*Glass roof: Although I love the panoramic overhead windshield of the Model X, the glass roof of the 100D, now standard on all versions of the Model S, disappointed.

First of all, it doesn’t extend forward enough to be part of the driver’s normal field of vision. So you don’t even notice it visually.

Second, it’s so darkly tinted that it triggers no sense of airiness or brighter ambient light in the car. (It’s so dark that I was able to view the recent solar eclipse through it while wearing two sets of sunglasses.)

And finally, on hot sunny days, it literally gets too hot to touch from the inside, radiating uncomfortably downward and adding tremendously to the air-conditioning load.

2017 Tesla Model S 100D [photo: David Noland, owner]

*Empty dashboard: With no Autopilot option, the screen behind the steering wheel of the 100D appears forlornly empty.

In place of the lovely blue speedometer arc and the orange/green power/regen meter arc of my old 85, there’s just a small rear-view picture of the car and a lot of black space.

The power meter, which I found extremely informative, has been relegated to the tiny, barely readable window to the right side of the screen.

*It ain’t green: Sadly, a couple of years ago Tesla discontinued the gorgeous dark green color option I’d chosen for my old 85.

For the 100D, I reluctantly chose “midnight silver”—really just a dark grey. It’s okay, I guess.

2017 Tesla Model S 100D [photo: David Noland, owner]

Bottom line

My new 100D is a car I bought for the future as much as the present.

I may not fully appreciate it until 2020 or so, when, on my annual drive to California, I set out on a 250-mile autonomous leg in the snow.

But in the meantime, while it doesn’t transport me into a new realm of driving euphoria just yet, the 100D is still clearly a better car than my old 85.

Which makes it, even more certainly, the coolest freaking car in the world.

Again.

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