Fitting of an ECU?

get a 2nd hand one from a car spares place. simple plug in

If you just get the EXACT same ECU if won't need to be reprogrammed. Take the ECU out and take it to a junkyard and ask if they have one (give them the exact car year, name, model, etc); the numbers stamped on the ECU must match up EXACTLY with the one from the junk yard. If they do, buy it. If they don't, don't buy it.

Note: I actually bought an entire car just to get the ECU. It was cheaper to buy the car than to buy the ECU. And it worked, because the two cars were identical. But they MUST be identical.

Go to junkyard; they will probably have one; you may have to call around though. Call many places. Somebody will have it. And it will be probably be only about $20, compared to buying a new (rebuilt) one from an auto parts store that will charge about $350.

I'd phone around the scrap yards and try to get an replacement ECU out of a car exactly the same model as yours. Not sure if all cars are the same, but when I needed one, I was told every one was different, even if you got it out of another polo with a different spec

It depends if the ECU is programed for that particular car because ECU builders design each ECU for each car manufacture. You would need to get a ECU from VolksWagen for it to work in your car.

ECU's have code #'s if you call a salvage yard and give them the #'s off yours it will be a direct plug in

take John's advice he should know being a mechanic

No just plug it in and go

dealership does em.