Vandersteen 5A biwire shotgun absolutely required?

Do it right for heavens sake. Presumably, your amps are in between the 2 speakers so that you have short speaker cables and long interconnect. That is what Vandersteen recommends and that is what works best. Bi-wire must have 4 seperate wires to each speaker, otherwise it is compromised. When you spend that much for a speaker, a couple of feet of cable shouldn't be an issue. I tried all brands of speaker and interconnects, and I like Anti-Cables the best. Those high priced spreads only cost more, but do nothing more..many times less than the Anti-cables. These are solid core, and sound the same in all frequency ranges. Try it... cheap and good...something nearly never found.