Why do you think Bi-Wiring improves the sound ?

Maybe getting higher quality jumpers rather than using the typically crappy factory ones would be a factor too.

Definitely for the high quality jumper vendor. He'd have your money.

I should have asked if bi-cabling or 2 seperate runs of cable sound better ?

Better to whom?
Different? Possibly.

I've since come to see that the amount of benefit of a power cord depends on the application.

What a concept: S Y S T E M    D E P E N D E N C Y
Who'da thought? <vbg>

As oft opined, any specific claim is only valid for the claimant! YMMV

Simple answer on question on if bi-wiring improves or not sound is - yes, it will improve sound.

The longer cable is, the better improvement will be. Alternative to bi-wiring solution to improve sound could be mono-blocks closer to speakers, and shortening cables. If speaker cable is 2ft or less, bi-wiring will not improve anything much.

Main reason to have bi-wiring option is a fact as speaker is not linearly behaving load, and therefore sharing cable connection resistance and inductance will increase intermodulation between low/mid/high. For low freq. speaker resistance of cable should be lower than mid/high, because speakers (almost) never use crossovers with additional in series resistor for lows, and also utilize lowest ESR Inductors $$. Mid/High  crossovers typically have couple of Ohms in series resistors, and therefore 100 mOhm cable resistance does not make any difference. The most important for Mid/High cable is to have lowest as possible inductance. 

@sfischer1 

Thank You and very well presented .

@ieales

Negative retorts are not appreciated ,
you have your opinion about the subject as do others ,
respect that's R E S P E C T to quote Aretha  .

I think I'll listen to her album next .

My  Mission Cyrus 781 speakers were specifically designed to be bi-wired...At the time I experience a better sound when I go with the dual cabling........