One of the videos I posted on here, I'm going down one of the local twisties and come up behind a Mazda Miata with the roll bar hoops, oversized tires, etc.., going 45mph. Another time, on another twisties road, I came upon a new "427 Cobra" Mustang.. going 45mph.
I know what you mean, faster and better handling the car, the slower they go in it.
Though Corvettes are a little better, they usually go 55mph, maybe 60 on a brave day.
My theory. Slower they're going, the shorter straight it takes to pass 'em.