All young fellas play with cars, even fellas that aren't so young anymore...
At first you'll play with cars because its fun, then later because you have some things on them you want done, and finally you play with cars because they break and you simply have to. Occasionally you will still play with cars because you can, because you want something that makes your car go harder, perform better or just plain look good.
These days I find working on cars hard work, frustrating, hot, tedious and plain annoying - but I get a great sense of satisfaction when the job is done :)
I'm not an expert, just a dabbler, be careful undertaking any of the work and modifications I suggest here. Work safely, and enjoy!