Re-spraying a car part, what do I need to do?

[yummyumm]

Hi, I have just bought a part for my car off someone who was scrapping their car. It is a different colour so I would like to spray it to match mine. Having never done this before, I don't really know where to start. It is currently dark metallic blue and it needs to be dark metallic green. Will it need to be primed first? and where is the best place to get the paint from(it's a BMW)
Thanks in advance for any advise.

[NORMANTHEDOG]

first of all what is the part you have bought,if its a wing mirror or small part,then you should sand it down with a wet and dry paper,(very fine grade)clean it off and then prime it with a grey primer spray,rub that down with same paper and spray on colour,3/4 coats should be enough,dont spray too much on at one go or it will run,leave a few minutes between each coat,then when thats dry add 3 to 4 coats of clear laquer. you can buy all you need from halfords. if its a large part like a wing or door,i would get it done at a body shop.

[yummyumm]

Thanks for the answer, it was very helpful. It's the surround panel for the grills at the front, I only bought the car a few weeks ago and the panel currently on it is quite rusty so I thought I would try and replace it (well, might have to get the Hubby too!).
Thanks again.