I took off the spider diff last night to change the 26mm o-ring which broke for no reason and sprayed silicone oil on my brakes and all over the nearest parts and wanted to change some of the screws also.But i thought those screws were the same as on the standard diff just a little longer,it seems that these are 2mmx22mm flat head.Where can i find such screws?
Hexcrews.com doesn't sell this size and i only have 3mmx20mm!

You need to get yourself the right screw bags as spares chris, delivery can't be too bad on small items like that, and you could go for the switch to titanium screws at the same time. IMO you can never have too many screws, buy all the spare screw bags for your car, and you won't have these problems (machine screws or tappers, hex or standard, etc., just get the originals).