There's no easy way to tell you to use <this car> with <these tuning upgrades> to make you win by <this much>. There's no way to tell how good you are, how you will find the cars, how you will cope with driving that same track over and over, what mistakes you will and won't make...
Too many variables. Best thing is to have a read around the forum and then try it. And don't forget to write it up in the race reports.