There are numerous T-amps available on ebay. I've bought one t-amp from ebay, one from obadimports.com, and have also bought numerous pieces of audio electronics and electronics in general from ebay coming from china/hongkong and I've never had to deal with customs.
I don't know if it has random enforcement or if the onus is on me and I've been unknowingly skipping it, but it never has been a problem.