It's going to depend on what the aprt is that needs replacing mate - you could always take it to an auto-electrician, or someone who is independent but has the diagnostic tools to double check, but that'll cost you.
It's likely that the part will be a main dealer part only as well, so the only thing you may potentially make a saving on intially is labour, but if the car then has to go onto Daewoo/Chevrolet's computer to re-programme the car, then you're not really saving anything