Different lengths of interconnects ??????

No issue. Electrical signals travel very close to the speed of light. You cannot possibly hear the difference. Since these are line level signals then the voltage drop will be negligeable too (your speaker should have very high input impedance something like 10 K Ohms).

Generally XLR cables are made from 22 or 24 AWG wire so you are looking at 16 to 25 Ohms resistance per THOUSAND feet. So on a 100 foot cable you are looking at a voltage drop of 2.5/10,000 = 0.00025 volts on your 2 Volt reference signal hardly worth bothering about... it in fact at extreme lengths it is cable inductance/capacitance that you may worry about.

Remember studios use microphone cable lengths of 50 feet all the time and a concert may involve 100's of feet of XLR cabling across a stage and to the control booth.

There is absolutely no need to be concerned over a few feet.

(BTW There is also no need to spend more then 20 bucks on an XLR microphone cable in my opinion...Mogami for example make nice cables and these may cost you $50 bucks...generally good cables last longer and have better shielding, however shielding is not likely to be an issue for short runs)

It is very interesting that most member in Audioasylum believe the cables must in equal length for both channel, but I do not know if they can tell the differences when the cables are in unequal length.

Not surprised at that. It is a good rule of thumb especially if one side is very much longer. I would not use unequal lengths but then again I would not spend so much on cables so it does not matter to me as the cost to get equal lengths is a negligible issue.

My suggestion would be to buy some less expensive highly respected Mogami XLR from a music shop or something with Canare wire or whatever floats you boat. Spend only $100 bucks or less and get equal lengths.

The draw back is that that these XLR cables are not called "Valhalla" and few audiophiles will go "ooo", "ahh" and "wow" when they peruse your virtual system one day to ask you about cable synergy. You might even get the opposite...questions like how in your right mind can you connect those great speakers with ordinary wires...no gold no silver ? If these comments make you feel insecure then by all means spend the extra money (like the ladies who only wear Prada) but then as the man from ING says in the adds you could also be smart and "Save your Money".