well of course you knew a post like that would get replies. Welcome to the miles of smiles club
Ummm, IAP is a long way from being your one-stop shop. in a moment I will list some more, after a carefully placed word of advice....
Just because they tout Fiat parts does not make anyone the best place to find parts for this car. Carefully price shop as well as quality check the parts and the suppliers. Near identical parts can vary widely in price.
also, do not rely on the assumption that if it is in the catalogue then it is in stock. in the same token, do not assume that if you do not see it, it is not available. no catalogue is all-inclusive. Also, never downgrade the concept of using used parts, or stuff you find from your fellow Fiaters.
i do not advocate publicly one supplier over another. i can say that i have personally used all of the below listed, and have not struck any from future use. of course, there are others on this forum who will readily respond with their favorites too. stay tuned!
http://www.webercarbsdirect.com
http://www.rockauto.com
http://www.international-auto.com
http://www.vickauto.com
http://www.fiatparts.com
http://www.fiatplus.com
http://www.baylessfiat.com
have fun with that new ride. it will be fun.
Hello from BC Canada. My girlfriend just bought herself a 1981 Pininfarina Spider 2000 Turbo. The car was from California, so as you can imagine, it has NO rust anywhere on it, but it has much sun damage to the interior. It looks like there will be many hours of quiet enjoyment as i work to repair these small things. I have been busy trying to find all the manuals and suppliers that i can for it, and it seems that IAP is the only one that seems to have it all........Except ANY info on the turbo system! this may be the achilles heel on this car. If anyone knows where i can find parts or info on the turbo i would be very grateful. 
Thankfully the turbo appears to be operating just fine at the moment. I can't believe how much fun it is to drive this car on our coastal mountain roads here in BC, it was obviously built for just this purpose! LOL i am now going to start looking for another spider for myself.....since she won't let me drive hers much. Maybe we will start a club up here!