Id not make any spur of the moment decisions. Is your car paid for by credit? If so, work out if you can afford the repayments while you have no job or stay put for the minute if its all paid for.
Theres no way to predict how long youll be out of a job, but the typical period is 3 months. Id wait a few weeks and see how youre doing cash-wise. Unfortunately, this is not the time to be fulfilling dreams of more powerful cars! If necessary, you could sell the car to rejuvenate your cash situation - but by the time its sold you could be in a new job!
An older hot hatch like a Williams is not cheap to run in terms of insurance, repairs or general maintenance. Id not recommend one to anyone who had just lost their job!!
