I wouldn't do that unless I had a reason to charge them more. This part might be $35 on ebay, but shipping would be like $10-$15 since it is a car part. Not much in profit. If you go to a junkyard and grab up a whole, function intake manifold for $20 you can resell it. Just get it ported and polished properly (do the research first) and you could sell it for a lot of money. Hundreds. Actually, it might be a bad idea unless you have a whole lot of knowledge and some experience in this field. (not to be attempted by amateurs)
I have a friend who makes his living off ebay. He travels around buying nick nacks from secondhand stores and resells them on ebay. He and his wife have done this as their main source of income for about 5 years now. x
There are great money opportunity's on the web trust me..my main income comes from the web (won't give my secret away lol). Right now i am making around 2500 a month but i am planning on expanding