Dentistry from Ebay – suitable?

Hello guys, with my Marea Weekend the timing belt is due…with also of course water pump and V-belts. A friendly car mechatronician would make the change quite favorable however I should bring him the parts. But now he said I should be careful because it often says with Ebay that it fits 100% and then still does not fit … the experience he had to do according to his statement already more often. I have a Fiat Marea Weekend SX 1.6 16V with 103hp with first registration 1997 h me now looking out the following products: V-belts:http://cgi.ebay.de/…/200433047924?… Timing belts:http://cgi.ebay.de/…/390327607541?… orhttp://cgi.ebay.de/…/360377686289?… Water pump:http://cgi.ebay.de/…/260778681897?… That should actually fit or? Isn’t that why he’s dismantling everything so far and then something doesn’t fit… has a lot of experience about such products and can give me a recommendation? Thank you in advance!