what the hell is this? sounds super scammy?!
It is a scam. The real WEX site will not charge you anything for registering or to trade. They will definitely NOT email you with an address to send money to either, the real WEX would not do that. Any legit exchange will not do this. Don't send anything to that address.
why does btc always trade at ~$400 higher on this exchange?
I have no idea, honestly. It's probably got something to do with their deposit and withdrawal process but i'm not sure what is the exact thing that is causing the price being so high compared to other exchanges though.
BTC-e used to have cheaper rates than all other exchanges.