I Used GTAIV Handling Editor to increase the steering lock on every car, boat, turck 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 much and using the hand break.
Also when your car starts spinning out of control turning out of the spin will actually work now where before it didn't do anything. This makes driving much more fun.
I've tried most of the available mods and this one is the best so far. I found others I liked but all seemed to have an annoying flaw like constant rollovers or monster cop cars. Abit more top speed would be a plus, but over all, just a nice calm improvement that doesn't crash the game constantly. 5 stars from me.