I've been to the limits of a car's performance at both ends of the spectrum.
When I was just starting out after graduating college, I worked with a Manufacturing Engineering gentleman named Sam Hawley, who owned a 1914 Model T Tourer, the last year of the brass radiator Model T.
He lived in West Springfield, Massachusetts, not far from where Ted Geisel (Dr. Seuss) lived and we went to Sam's place for a graduation celebration for one of his grandkids (Sam was a couple of years away from retirement when I first met him). During the party and as was Sam's habit, he gave anyone who wanted a ride in his Model T so, after all of the kids had had their turns (some more than once), he gestured to me and my wife to hop in alongside him and off we went. It was smelly, and bumpy, and noisy, and had a lot of wind blowing around - In short, it was a LOT like riding in a Speedster, just 4 feet off the ground!
We went south out of West Springfield headed for Connecticut and as we got away from the neighborhood Sam gets a big smile and says "Hang on, you two, I'm gonna OPEN HER UP!" and off we took, down this back road as the speed increased and the wind blew and the car shook and that little motor was chugging for all it was worth. Kathy was scared, I was scared, little kids on the side of the road stopped their bicycles and turned and they looked scared (and their dogs turned and headed for the hills as Sam honked the big bulb horn at them).
After maybe a minute that seemed like an hour of wind-blown torture, Sam slowed down to a more normal speed and said, "She really flies, doesn't she?"
Kathy and I were both ashen-faced and just nodded that she did, indeed, really fly, especially when one is sitting almost 5 feet up on a horse wagon that's swaying back and forth and the wheel vibration becomes very harsh above, say, ten miles per hour. I thought sure we had been doing close to 80mph on that old back road, perched up way high on those Conestoga Wagon-sized wheels, white tires and all, and a little bit of steam coming from the radiator cap that wasn't all that far away out in front of us.
"Geez, Sam..... How fast were we just going?, I asked.
"She was really wheeling!", said Sam....."But she's all done between 35 and 40!"
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At the other end of the spectrum was a ride for charity during one of the Hilton Head Island Concours weeks. For a $150 donation to a specified charity you could get three laps around Roebling Road race course (Not far from Savannah, Georgia) in a new Ford GT with Bobby Rahal at the wheel. I figured THAT was never gonna happen again so I ponied up my Visa Card and got in line.
My turn comes, Bobby pulls up to the start/finish line, some really pretty Southern Cheerleader-type lady hops out, I get in and someone helps me with the ( seemed like 27-point ) seat belt harness, the door is closed, we introduce each other ("Oh, you're the guy with that white, racing 356!", says Bobby. So then I had to tell him what it was and what the engine was, yadda, yadda because he had been watching it go around the track (fast parade laps) and loved the exhaust note, so he said)
Then, we take off. Like a friggin' Tomahawk Cruise Missile. No tire screech, no fish-tailing, just slam you back into the seat acceleration. We get from the start/finish line to the first right turn in less than 1/4 the time it took me in Pearl, he lets off the gas way later than I ever would have dared, STANDS on the brakes, blips the gas, downshifts two and stands on the gas. WHAM! We're off out of that corner like it's a fireball, heading towards the back stretch.
The back half of Roebling is a few sweepers that get increasingly tighter, then into the final right turn to the front straight. He heads into each one way deeper than I thought anything could and comes out of the apex with his foot in it, and all the while he's calmly asking me about my car and telling me about how the original GT-40 and THIS Ford GT are so entirely different, like the GT-40 was naturally aspirated and made one helluva lotta noise in the cockpit from the engine in the back seat. The Ford GT has twin turbos which really block most of the exhaust and intake noise so the cockpit is surprisingly quiet (you can have a conversation at speed). It also has a very effective traction control system that seems to anticipate your next move and seems to already set up for you before you act. He's telling me all this while he's calmly negotiating the track in, what I found out later, was the fastest lap time of the day - OK so the other cars were vintage racers, but still - Wicked fast.
As we come around to the front stretch he opens it up and we rocket down the stretch and I watch as the speedo rises up to around 150-ish and he brakes for the right turn. "152!", says Bobby. "That's about it for this track. The front straight is too short before you have to brake for the turn. Take this car to Daytona or Talladega and it could break 200, for sure. Ford really pulled out all the stops on this car!" Meanwhile, I was beginning to get that ashen look again so the next two laps were a bit (OK a LOT) slower, but I was certainly impressed. I told him my measly 140 HP did OK, but this thing was a whole different concept.
"Yeah, they're pretty slick. When they told me I would be driving this around for a day I was tickled. It's a blast out on the street, to!"
We got back to the start/finish line and I crawled out of the car and found that my knees were weak and I had to stay still for a few moments til things settled down again. Then one of the track guys took my helmet and said, "Well..... How was it?"
All I could say was "Holy $#!+"