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

I think it is likely ideal… but dependent on your components. I have been working on my system for fifty years. It has been a mishmash of components for most of that time. 
 

I have invested a huge amount of time and discretionary income in my system… doubling the investment every decade. You can see where I ended up… under my user ID. All Audio Research electronics, all Transparent interconnects, cables and power cords (save one). I never set out to harmonize my electronics and cables… it happened through extensive experience, auditioning, and evaluation.
 

One day I ended up with the best system (for my tastes) I have ever heard… and it turned out to be a known synergistic set of components…. Audio Research,  Transparent, and Sonus Faber speakers. Hmm, this can’t be an accident. 

I have Kimber for speakers and interconnects and Shunyata for power/distribution.

I also added 1 item at a time and appreciated the difference.  Part of the reason was after I bought my speaker cables from Kimber - I looked at eBay for kimberdirect and bought demo's for my interconnects.  (I do have the same interconnects for source to pre and pre to amp connections.)

@styleman

I use a mix of different cables for interconnect, speaker and digital cables. I have no complaints. The music sounds great

I would say your own results speak for themselves. Different roads do lead to Rome. Same brand cable loom has worked out for many. Use your ears (As you’ve apparently done).
I have used the same manufacturer for my Line stage:amplifiers/speakers (Coincident) to excellent effect. But have two different brands of cables (Ocellia IC/SC and Lavricables power cables). It has worked out very fine for me.

Charles

I’ve done it both ways over the years. Initially, it was an ad hoc mismatch based on a very modest budget for mid-fi to entry level hi-fi systems. Frankly, I didn’t know any different back then, and ….with the comparatively modest audio performance capabilities of those earlier budget systems , I doubt that a single array loom of cables would make any big difference in any case,

BUT .,. When I moved into high-end systems with a contemporaneous introduction to high-end cables , …then MY experiences ( emphasis added …,,,) dictate that it does provide a distinct step-up in audio performance to have a same brand AND same model (or better) cables loom.

It’s currently an all-CARDAS CLEAR / CARDAS CLEAR REFLECTION array that superseded an all-NORDOST FREY array.

Budgets matter …it was a piecemeal 2 year migration with all purchases being pre-owned listed on major audio forums. ( mostly CAM…) It was the ICs first, then power cables next, and finally, the speaker cables last.

In fairness, my selection ranking above was actually simple serendipity of available items on the master wishlist just popping up, rather than a rigid plan .

If I was buying new, I would have started with power chords, then ICs, and then speaker cables.

FWIW ..,

Thanks Guys for your input.  I agree with what Charles 1 Dad said.  My ears tell me that I'm doing fine. It was an  expensive route to get where I am in my present system. My instinct tells me that any increase in SQ by building a loom system with one manufacturer (Nordost, Synergistic Research or many of the other respected brands) would not be noticeable to me.  I'll just follow a route that makes economic sense to me (but I won't go cheap) without religiously adhering to one brand.