Hi everyone,
I just signed-up here because of this posting, I normally post on another pipe forum.
Amboynia is the burl form of Narra wood (Pterocarpus indicus) and it can have toxic affects to people depending on their sensitivities. This includes respiratory problems from inhaling sawdust and skin irritation from exposure (though rare). I learned this when working with Amboynia burl as a hobbyist.
Unless you are absolutely certain of your immunity, I would not recommend using amboynia/Narra woods as a pipe material. It can cause very bad reactions if introduced to your lungs.
Here's a couple links from woodworking forums about toxic woods:
http://www.wood-database.com/wood-articles/wood-allergies-and-toxicity/
http://home.earthlink.net/~wooddude78/woodlib1_2.html#L