Test Drive Unlimited
All the races in the series
You start off with one race unlocked. As you win, the next race gets unlocked. Win them all in the series and the car is yours.
C/D class Saleens
If you have not bought a Ford Mustang GT Coupe and a Ford Mustang GT Convertible, do so. Take them to the U.S. Muscle Car Tuner shop. When you get there they will ask whether you want them tuned as a Ford or a Saleen. Press Down and select "Saleen". The new car(s) will have a very visible sign that says "Saleen" at the top of the windshield. They will also be upgraded to C/D class cars.
Easy Master Points
To get easy master points,you can either 1.Drive behind another racer to do slipstream or 2.Get a fast car(I used the Koenigsegg CCR) and drive on the highway for as long as you like, the points will come faster if you drive faster.
Easy money
Go to the bottom of the map by the crater. There is a speed challenge there that awards $40,000. A C-Class car is required (TVR Sagaris recommended). You can do it in about 1:30 to 2 minutes and get $40,000, which results in about $1,200,000 after one hour.
More money
Find the highway and go to a spot near but not too close to an intersection. Find a racer and get them to have a Instant Challenge with you.. Set the finish line just behind the start line on the opposite side of the highway. Once the race starts immediately turn over the center of the highway and drive past the finish line. Do this five or ten times then do a race that is worth about $20,000. You will get a lot of money for the win. Note: This does not always work.