The castle motors from China are actually copies of the original ones but they are still very good motors for the price, as good as any other Chinese motor anyways. I know a few people use them same motors on 6s for speed running and have ran over 115mph with them.
the goolrc stuff has a good reputation with most people for being a good budget option for general use, I have never had any issues with them and others will swear by them for bashing purposes.
never had any experience with the surpass stuff sorry
dont worry about customs charges from China, it’s none existent as they mark everything down or as gift anyway