Does creating a loom in cables in a system make a significant difference?

Only if you want to work the rarely used word "Loom" into your vocabulary. 

Just using AQ Blizzard Xtreme powercords all around, Cardas Gold Presence interconnects, and speaker cables are Kimber 12TC. I try to keep it simple......

@styleman   im the same way, havin a variety of good ICs i got t a decent price. i decided to do one system in all the same cables, so i got my desktop system, which nearly all tube also, in morrow audio. was gonna do another system in all blue jeans but i just havent gotten around t it yet, plus man those BJC RCAs  dont easily fit the back of my marantz

Results will vary and it basically comes down to trial and error.

boys and girls... it is a chain... so every link matters... up the chain can be said to have more influence through the whole chain than further downstream due to its position in it, but the signal is all traveling downstream... right?