1) It is a fact that almost no FTP server can be connected from outside nowadays. I said "almost," since I didn't test this out recently, so I cannot tell for sure.
2) As for bandwidth, VPN still uses the network link that you are using per normal (i.e. the NTU network). In fact, VPN increases the network communication overhead (both computational power and network bandwidth) significantly. So if you need more bandwidth, I don't think VPN helps.
