Unlockable races and cars...
Any car you can play in Quick Race from beginning can get two new liveries (maximum total of three). The first is unlocked after driving 20 miles (32 km) with the same car. The second livery is achieved after driving 50 miles (81 km) with the same car.
Reach the Final Master Series. Then, enter the Sega Rally Final. The Lake Side track is the last course in the four races. It will now also be unlocked in Quick Race and Time Attack modes.
Get 100% in Championship Mode.
Press [Accelerate] about halfway down. As soon as you get grip and the car lunges forward, press it down all the way. This will help you to not get stuck, even if you start in deep snow or deep sand.