will they ship to the US?
Yes.
and what should I buy?
There are only three things to buy at this time: Extra docking sleds, extra remotes, and extra power supplies. Buy one of each.
I was considering buying an extra mount, though I'm not quite sure why I might need it. Is this foolish?
You would need it if you intended to build a home docking station or you wanted to put the empeg into a second car. Or if your car was stolen (with the docking sled still in it but the empeg in your hands).
What about the adapter or remotes? Should I buy one of them?
If you like the Rio remote, you would get an extra if you thought you might lose the original one. However Kenwood remotes also work, they just aren't labeled properly and they are missing some functions (see the button guide at
www.riocar.org for details).
An extra power adapter is not necessary since you can buy other third-party power adapters. However the one they are selling is the compact plug-top style which gets high praise from those who own it, and it is rumored to be less suceptible to ground loops when plugged into a home system.
If I weren't broke right now from the Con I just went to, I'd be buying two extra docking sleds because I've wanted to build two indoor docking stations for a while now.