There is a lot more to a sports car than top end. Acceleration, handling and braking are all markedly better than the average automobile. Having superior performance in those categories makes the car safer, not more dangerous.
Among those, only acceleration is a function of the engine, and most economy engines are still capable of excessive acceleration. Aerodynamics only significantly affect top end and acceleration, so we could easily build a Chevette with the handling (okay, that would take some serious lead in the floorboards to move the CG - let's say a Sentra instead...though having owned a Sentra, that might be a bit of a stretch) and stopping traits of a Ferrari by changing the wheels, brakes, and suspension, and moving some weight around to get the CG in the right place.
Of course, the recent Mustangs make a good counterexample; though it's never been publicized in any other way, most of the long-timers around here know exactly where I'm talking about when I say "Mustang corner" because at least four of them have gone off there in recent memory. Big engine, not-so-bad handling, but incredibly crappy brakes that overheat too quickly on the backroads here, and cease to be properly analog just in time for a sharp corner with a little rise on the approach. Yet it's still a highly desired sports car because it's fast. The classic Camaros took a related but different approach, with a huge engine, good brakes, but handling reminiscent of a container ship. They rarely make it to Mustang Corner because nobody wants to fight them around the other corners.
(Oddly, pickups rarely run off at MC, in spite of the number of goober kids around here that try to drive them like sports cars. I suspect this may be another "don't make it that far" situation, since MC is one of the few places a pickup wouldn't be able to get itself back on the road, while there are plenty of other corners approaching it from either direction that will knock some sense into many drivers while still allowing them to limp their vehicle away before the landowner finds them.)
I know a number of such owners who take their driving (on the street and on the track) very seriously, and they rarely get into collisions.
I'm one of those people - or was, when I could afford to be. Still, every collision I've had has been under 35mph, and three of the six involved backing out of parking spaces. (One of the others involved mechanical failure, and another was being backed into while stopped at a light. The last, I wasn't looking far enough along the cross street at a yield sign.) That doesn't mean my current driving record reflects anything other than my ability to not get caught. (Which includes not hitting stuff, since that tends to get one caught.)
Maintaining a track-only car is a lot cheaper than keeping a hot sports car fully street legal, and a lot easier on the nerves. (Total it or blow the carefully tuned engine, and your regular car is still waiting to take you to work in the morning.)
Actually, there used to be a variety of swoopy-looking kits that fit on VW Beetle chassis. I always thought they looked cheesy, but enough people bought them to keep the manufacturers in business.
Those things still just look like melted Beetles. Nobody's building a 50MPG 55HP Viper lookalike. Think that could be because people don't want one that can't smoke the tires and go triple digits?
