or buy a newish 1.2 16v. can be picked up for reasonable money and, would only cost a little more than dropping the newer engine in your car.
unless your your engine is completely buggered and the newer engine is cheap, then i wouldnt bother. the cost of putting new engines in is quite dear really, i was quoted 1k! but then if you can do it yourself or know of someone who could do it cheap then it may be worth looking into.