Muscle Car: find 4 keys in any track; press down at gear selection screen.
Hot Rod (Rocket Car): find 8 more keys in the other tracks; press down at the gear selection screen.
City Bus: find all 16 keys; press down at gear selection screen.
Police Car: finish 1 player GP Mode; press down at gear selection screen.
Taxi Cab: finish 1 player Circut mode; press down at gear selection screen.
There are four keys in track 2. The first key is where you see a danger sign go to the left. You should see a yellow ramp. Go slow around it and turn real hard. Right behind the ramp is the first key. The second key is right when the road splits into two parts. Go to the left and go off the jump, but stay to the left side of the road. Whenm you hit the jump if you are going fast enough you will land on a road, but you have to hit the brakes hard and turn around. Go back, but don't fall off. You will see a key to the left when you turn around. The third key is when you see the large truck, go under it and hit the ramp. If you hit it just right you will land on the top of a building. Follow the rooftops until you see the third key. The last key is located right after you get the third key you have to hit the ramp and jump onto the other rooftop. When you get on the other rooftop you have to go through the cones and land in the grass. Drive through the grass until you see the key. Once you get the key all you have to do is finish the race.
Off of the start turn right hard into a little maze and there is the key. Next, After that first big turn, there is a little hill. Instead of going right, go left and the key is on the right side of the right house. After the huge jump, befor the turn, there is a little cut of wedge in the building. The key is there. And last, go stright over a few ramps and jump over the wall. But, you must turn around and the key is right next to the wall.
The first key is next to the ramp you go down. After going on it, turn around and go the other way next to the ramp. To get the next one is very very hard. You must avoid the big turn by going over the ramp through the building. But, you have to stay on the next platform after he ramp. The key is there. The next key is in the right tunnel when the road forks, go left and then turn left when the road gets straight. Go through the right tunnel. And the last key is on the left side of the left box near the shortcut under the building.
On Track 2:
Go through the little tunnel to the left near the beginning. Instead of going right, go left off the ramp. Go under the truck to get the key.
On track 3:
In the beginning, go straight through the building. After the big jump, go over the little one and go left (key). After the long stretch of road keep going straight.
On track 4:
To avoid the sharp turn, after going down the ramp, go right off the ramp. Go left on the fork, and then go left through the tunnel.