There are a lot of ways you can go about upgrading a car or truck. I find it is fun to get an older muscle car and customize it from the ground up. I find that it ends up getting me a nice car that is a blast to drive. It is usually cheaper than buying a brand new car anyways. If you want to get more performance out of your car then aftermarket parts are a must. The first aftermarket part I would suggest would be a supercharger. It will give you the most bang for the buck compared to other parts. It may be beneficial to just get a crate motor that is already tuned for high performance. That is what I usually do as soon as I buy an older car. I do not think it is worth putting in thousands of dollars into an older engine that could quit at any time.
Another thing to look at is aftermarket suspension parts. Going fast is great but if your car drives like a tank then it is not as much fun. A great sports car is quick and nimble so I always get brand new suspension parts. A performance exhaust system is also a good way to pick up some extra horsepower. It will also make your car sound really good compared to the stock exhaust system. I am pretty happy with my current car but I always find little things that I can tune just a little bit. There is no reason everyone has to spend the amount of time and money buying parts for a car. A few smart choices in parts can really make the difference in performance. I drive my car every day and it really makes my long drive to work super enjoyable.