DXE? There's no such company to my knowledge. If you're referring to DXS, I don't believe they come in a 91ci version. Seems rather to silly to buy a DXS or CP tank anyway if you plan on using a harness for it, they're expensive in large part because they're so lightweight.
it's up to you, but i find that with a remote line, your marker doesnt' balance correctly without a stock...and that sorta defeats the purpose of the remote line.