I would agree with the above having used both of those and found them both to be fast and well stocked. Also Losi parts warehouse are very good too, based in the states but if you're buying a few things it can work out cheaper (not sure now with exchange rate). Also surprisingly quick.
What I do is download the exploded view with all the part numbers on and use it as a quick reference and then just type part numbers straight in to any of the above sites.
Cheers
Chris