I'm assuming you've done some extensive testing to back this claim?
I personally have never once seen MP slowed due to wires..... Believe me you I go nuts with wires being everywhere do to my OCD about having a light switch for every room and a switch for just about everything, spot lights, alarms, outer defenses, turrets they all must have an on off switch lol...my friends get annoyed sometimes because of this lol. I've never heard of or ever seen a drop in FPS or server FPS due to wires or any kind of lag.
I'm honestly curious to hear your explaination regarding your claim. thanks