Bi-wire v's single with jumper leads.

There's a very sound reason why bi-wiring works.

Remember that your crossover is basically a filter that splits the signal inside your speaker and sends the highs to the tweeter and the lows to the woofer. Up until that point, all frequencies travel together along the single speaker cable.

By removing the jumpers and using bi-wired cables, the high and low pass filters become part of each loop right back to your amp terminals, meaning that the high frequencies can't travel along the woofer cables and vice versa. This helps to reduce distortion and smearing of the sound. It's very similar to the way S-video cables separate the luminance and chrominance signals to improve picture quality over composite cables.

But as Shadorne said, if your speakers/system isn't truly suited to bi-wiring, you may hear little or no difference.
At the very least, you've doubled your wire gauge!

Flashunlock "The 2-4 design is a bit waste of time and might as well use single wired with jumpers instead."

That couldn't be any further from the truth. There will of course be systems where conventional bi-wiring results in no audible improvement, but it's generally (in mid-fi & better systems) a very effective and impressive tweak.

To expand on what I explained earlier, 2-4 bi-wiring has the same effect as putting the crossover at the speaker terminals, rather than in the speaker, thus greatly reducing the distance traveled by the combined high & low frequencies.
Basic electronics will tell you that once any kind of filter exists in a circuit (eg a high-pass frequency audio filter as in a crossover), then the ENTIRE CIRCUIT is only capable of carrying what that filter allows.
As an analogy; if you put a 100 ohm resistor in line with 0.01 ohm/metre cable, the entire cable will have a resistance of about 100 ohms; the resistor dictates what that cable can carry.
Removing the jumpers and bi-wiring means the low-pass filter (for the woofer) acts on the entire LF cable right back to the speaker terminals, and same for the HF cable.