Super Grip:
The spinning tire and wheel icon is a Super Grip. This allows you to climb hills at 
full speed and have overall great handling for 20 seconds. There are 2 extra things 
that I have found to do with Super Grip so far and they are: 

1 - If you lose a wheel, get a Super Grip Icon and your car will level out and 
behave as though the wheel is still there. 

2 - In the Titan arena, get a Super Grip Icon and climb the outer slope at an angle. 
Then, as you are on the vertical slope, hit the Rocket Icon to be propelled. After 
the second Rocket Icon, get your car to the top of the turn and you should get the 
Bonus 3000 Points Icon.

Floating Glitch:
On the level, "Harbor," there is a glitch where you can float in midair. When you 
first start the level, you are in the back of all the cars. When you start going, you 
have to turn right, and then right again. Then, you jump off a ramp. After you 
jump off and you're on the ground again, go forward a little more. You'll notice 
that there are some boats to the right side. Using a fast car, face one of the boats 
from a distance and using your Turbo, just drive straight and get right on top of 
one. There is an "invisible" box around the boats and when you're on them, it 
appears as if you were floating. Look at your car from a side view (L1 or L2) and 
you'll see it perfectly.

Unlock Rough Justice and Bonus Cars 1, 2, and 3:
Come first on all arenas in Destruction Derby mode.

The Dam and Bonus Cars 4 and 5:
Place 1st on all tracks in Wrecking Race mode.

Brennan Playable:
Defeat Brennan on the Refinery stage to make him playable.

Bonus Bowl and Track:
To unlock a bonus bowl and track win all Races and Destruction Bowls in Single 
Races.