It's very easy to get this achievement for winning races in career mode. You can do this quickly & easy if you win the first 25 races of career mode. Just use the starting car until you get the new car & max it out as far as you can as soon as you can after you get it. The only hard races you will have is the ones that are in the 850's for recommended rank, but they weren't too bad once I got the lead with my new car. You should have rank 845 for the car when you max it out with 1 star on the car. Exactly. Thank YOU