If you are looking to build a car, there is an option other than fixing up an old car. You could also look at kit cars. Kit cars are a way to build a car from the ground up without having to engineer everything for yourself. Kind of like a functional version of the models you put together as a kid.
I am not talking about the kits that try to make your Fiero look like a Ferarri, but cars that give an actual performance upgrade from the base car.
One of the most well know is Factory Five Racing. They sell a Shelby Cobra replica (although they are not legally able to call it a Cobra) that uses Ford Mustang running gear. Even with the older pushrod 5.0 powerplant, the performance is amazing. How do they do that? Simple, you are putting the engine into a much smaller simpler car. That means it is lighter. And a lighter car with the same horsepower as a heavier one, will have better performance. The same with braking and handling.
They also have a hot rod style kit car, as well as others. All of them offering significantly better performance than the donor vehicles.
The picture at the beginning is of a Smyth G3F. It takes a VW Jetta/Golf donor car and you create a mid-engine car that weighs around 2200 pounds. You can even have it be diesel powered. All in all, that is a neat idea.
There are also ones that let you build a kit version of the Lotus Seven, which was all about light weight and performance from the factory, so it seems like a good fit for a version with more modern running gear. If you can imagine it, someone else probably has too, and there may be a kit version of it. If not, maybe you can create one.
I like the idea of having a truck show up with a pile of parts, taking what I need off a donor car, and putting it all together. Being able to build a car completely from the ground up would be a fun experience. And you would know how everything worked on it along the way.
To me, that makes kit cars sound like a lot of fun.