I Used GTAIV Handling Editor to increase the steering lock on every car, boat, truck and bike, except the bus by 10, which makes a huge difference. You can now make simple left and right turns without have to go really slow or use the hand break, and if your good enough you could probably make the turns without slowing down at all and using the hand break.

Also when your car starts spinning out of control turning out of the spin will actually work now where as before it didn't do anything. This makes driving much more fun.