interconnects & powercords on subwoofers???

I've tried a few different power cords and interconnect cables with my sub. Every after market cable was better than stock, that's for sure. Notes are better defined, basically.

However, I did not get any huge benefit from using an expensive Kimber PowerKord 10 Gold or DH Labs Power Plus over good $50ish Belden made cable, which I'm still using.

Same benefits with the sub cable, I'm using a DH Labs Subsonic which is not too expensive and is better than the crappy free thing I was using before.

Hope this answers your question. Basically, you don't have to spend megabucks to get the benefit over stock cables. DH Labs with their Subsonic cable, and Supra, with their LoRad mains cable and Sublink interconnect, would be two manufacturers I can vouch for.

I can agree with the DH Labs subsonic cable. I used some quality Cardas ends & my sub sounds better. Still using the Carol cable 12/3 I got at Lowes for the PC.

I use Signal Cable's best power cable on my sub and it has made a world of difference. Using VH Audio DIY instructions I have built 7foot solid core silver interconnects for the sub which was a major improvement over Monster etc.

Based on my experiences with my Rel Stadium 2 I will definitely say the answer to your question, unfortunately, is "YES", with utmost certainty. I say "unfortunately" because it's the proverbial double-edged sword. On the one hand, if it didn't make a difference you'd be saved the extra costs of both...while the good news is that it lends 2 additional avenues of audible system improvements through cable upgrades.
As for pc's, my Rel went from stock pc (the unit "functioned correctly" but only at perhaps 60% of its ultimate potential)...then onto a Signal Cable Magic Power which was a nice improvement (I'd rate it up to a solid 75%), improvements included a noticeable speed and agility increase as well as better bottom extension...).
Then I tried a Pangea AC9 which was a big disappointment...even after a lengthy break in it was a step backward from the Sig Cable and only "somewhat better" than stock..let's say it now went back to a 67%...
Then, a significant and thoroughly justified improvement when I switched to a VH Audio Flavor 4: MUCH faster, deeper, and much improved sense of power and authority... the Rel was finally showing its attributes and justifying itself in the system (also in my experiences a good sub not only disappears better but also adds a more natural presence, focus, imaging and depth to the overall soundstage that is sorely missed when not there, even with speakers you'd never consider lacking in the bass department). I would say the Flavor 4 pushed the Rel up to its 90+% of what I would imagine its potential to be. There must be room for more improvement but at this point the performance/cost ratio is above my wallet at the moment.
As for I/C's I had been using the supplied Speakon connector at first but had Frank at Signal Cable build me a custom one to take its place which I happily used for several years (also an improvement over the original, similar to the powercords... as it was better than the stock-to-Pangea but not quite the Magic-to-Flavor 4 leap). When I had to change rooms I also changed my Rel set-up and went with I/C's. Here I used "spare" Harmonic Technology Pro Silway mk 2's which did a fine job and stayed as my default for a long time. Finally, and just recently I had a pair of Harmonic Tech Magic 1 I/C's available and swapped them in place of the Pro Sil 2's ...not knowing what to expect, and lo and behold a significant jump again.... much more so than expected and even more dramatic than the Magic power to Flav 4 PC upgrade. This was a clear improvement in air and space, an even better sense of effortlessness, speed and "tightness" with the most seamless integration into the overall soundscape ever.
I know this is blasphemous but part of me had secretly hoped there wouldn't be much, if any difference so that I could sell the pricier Magic rather than the pro sil 2, but the difference was not only there...it was instantly appreciated to the extent that I couldn't go back again.
Anyway, I hope I didn't bore you with the specifics but sometimes I find passing on personal experiences help in someone's decision making processes.
IMHO, I would start with some kind of decent aftermarket powercord just to dump the stock cable ( there are a lot out there and a new system favorite recently is a company called TWL (Triode Wire Labs) which I'm having good luck with elsewhere including amps, pre, and digital...) as well as the aforementioned Signal Cable, etc.
I/C's you can explore on your own, as I'm sure you have favorites already worth trying, but the key here is: DO TRY!
Good luck and Happy Lissn'n

Thanks for the comments. I will definately try some after market pc's and ic's. Lissnr, thanks for the detailed imfo.

I really can't get over how much these 2 subs add to the music, it's amazing. Looking forward to trying wires. I have both subs plugged into a dedicated line.

Cheers

Sounds like you're in great shape, they say 2 subs are much easier to integrate into the system and having a dedicated line is ideal. The biggest lesson I've ever learned is : you can get pumped up by all the product hype but it really boils down to trusting your own ears regardless of what may be written or said by anyone else. Have fun...