I'm looking as well.
There are door shut seals on ebay but the window seals appear elusive and are apparently no longer available. I have seen posts where they have been repaired with quality sealant but if you manage to source some please let me know.
You can get the door channels on eBay for about twenty quid a side (plastic and rubber bits). I think Alfaholics have some too. I'm after a drivers side door rubber that the window glass goes through if anyone has one or knows where I can get one.
The window seals on the top of the doors are no longer available for the spider, and have not been for some time. Though I did get one from a main stealer for a GTV. This was a year or so ago part number 0060617926 was £50.20 and new clips 0060509720 ten at £1.60 each all plus VAT. Most Spider have problems with the seals getting old and splitting. I used some stuff called SUGRU, which is available on the bay and does a fair job, though you have to use a whole packet in one go, as soon as it is opened it starts to harden.