Hi and welcome to the board.
Don't worry about your English... already I can tell you speak it better than most of us! ;-)
I'd recommend you start by reading thru the
FAQ ... it's got tons of good information and will answer at least some of your initial questions. In particular look for a section called "Make your car faster" down a ways.
Once you're up to speed on the basics you're in a good spot to ask questions about the details.
Again, welcome aboard !!