I want to make a mould of an original car part that would be expensive to replace if I damaged it. Is there any way around this? I've tried using 3m 1080 vinyl wrap in the past on cheaper parts from the same car but that didn't protect the original part at all.

Personally, I wouldn't use automotive products. I know plenty of people on here do, so I know there are some that work, but I have attempted it 6 times with different 2k automotive paints, and each time resulted in failure. I don't do it any more. You could have more luck with 2k marine products, but they are more expensive and then you might as well go with Duratec anyway. Duratec is made for the job and will work every time. Otherwise, PVA is guaranteed success, it just requires a little bit of post-finishing work.