Personally I'd just go for cheap tricks, I'm assuming this is going to be a top down racer.
For steering pivot the cars around the back axil to make it steer more realistically (rather than in the centre)
If a car hits another car take the x and y speed of the hitter divide it by a number (play to see what looks right) and tranfer those velocities onto the car that got hit.
If you want to add spin to cars that have been hit, just do a quick bit of where the impact was reletive to the centre of mass (pivot point) and see it you need to throw some spin into the tin, again, just play until it looks about right.
Of course, if you're looking for really realistic physics forget all of this, but if you're wanting something GTA1 style then just look at fudges.
For steering pivot the cars around the back axil to make it steer more realistically (rather than in the centre)
If a car hits another car take the x and y speed of the hitter divide it by a number (play to see what looks right) and tranfer those velocities onto the car that got hit.
If you want to add spin to cars that have been hit, just do a quick bit of where the impact was reletive to the centre of mass (pivot point) and see it you need to throw some spin into the tin, again, just play until it looks about right.
Of course, if you're looking for really realistic physics forget all of this, but if you're wanting something GTA1 style then just look at fudges.