[agro1]

It makes a huge difference - mostly because you do not have to use the steering wheel as a brace to hold your body from flying around. A good racing seat will hold you in place allowing you to "feather" the wheel and give the steering good, gradual, precise imput. But what it mostly does is just give you more confidence and make you feel more attached and a part of the car and able to control it much better - plus they're safer.