When your in an iva do the companies expect you to give them all spare moneys left after your bills are paid or are you allowed to have something left for yourself

Myself and my wife are considering going into an iva , we have about 27k of debt that includes my car that is financed , would they take the car away from me ? I need it for work , I think after all our out goings we have about 250 a month left from our wages , any advice on an iva is much appreciat...