car engines specs and tuning, and then go out and buy them if they work for you. And they usually don't because there haven't been very many great quality cars under $5,000 in US showrooms lately. https://engineswork.com/
As a result, you will find most of the time that all the best used cars are not new at all. At that point, the best place to start should be with a pre-engineered car, or perhaps with a used car with extensive underhood work and service.
Here are a few things to consider before you buy your car:
It should be in good mechanical condition
The car should be free of problems that you know would prevent it from showing top performance. If it is in a major mechanical problem, you will want to go to your repair shop or car dealer for full service. If it isn't in an obvious problems like a cracked airbag, it will be much harder to track down a solution. You do the same research you would for any engine repair.