Model specific ones and forum related ones seem to throw up the best cars I find. When hunting for my spider there were some lovely ones on Alfaholics.
They the best 2 frank, like lewis says the others are model specific.....bit like maserstis....youd search on here 1st then PH......nothing else really
Not sure how the classifieds work on ebay but I think you can go and inspect in the same way you would any other car before buying, I would only bid on an auction having inspected / test driven it. My father has sold a fair few cars to Europeans via ebay, many don't look before they come to collect, if the advert isn't honest then they don't have to part with their cash.