In my experience, once you reach a decent level with your system, yes cables matter. When I started developing my current high end system 11 years ago, I started out with Acoustic Revive Single Core biwire speaker cables before moving up the Jorma line of sc's incl: Origo, Prime & Statement as the rest of my system developed. With each upgrade, I could hear a nice improvement in resolution, staging, tone/timbre & overall refinement. Obviously you're not playing in that league, but with your budget you could still get some very good sounding cables. Your MF amp is on the cool/dark side, so i'd look for warmer, richer sounding cables such as Cardas. Furutech also sell finished speaker cables which offer good bang for the buck.

Audioquest sell more cables in your price range & they're good. I used Audioquest Slate biwire cable on my Infinity Reference 60 speakers for years which only cost about $60AUD/meter back in the day. Also don't forget, cables like amps come up for sale on places like US Audio Mart & you can pick up a bargain.

Speaker wire size can matter, especially if the speakers are located a long distance from the amplifier. Generally, the larger diameter cable the better for longer cable runs. Typical cables are side-by-side conductors. I use two single-conductor wires that are bundled with wire ties to form one speaker cable, with the conductors slightly twisted around each other over the length of the run.

If you are doing a fairy typical length of 20-25 feet from amp to speakers, then your 12-gauge cables should be fine. If you can locate the amplifier between the speakers and shorten the speaker cables, that would be even better.

I believe I heard a difference between a 24-foot long 12 gauge cable vs. a larger diameter 8-foot run of 10-gauge cable. The larger diameter cable was preferred. I have not run a blind comparison to verify the difference is real or imagined. Since my amps are farther from the speakers now, I use the 12-gauge, 24-foot cables.

View Roger's history in the industry, his education, his test, then decided if it makes you feel better to blow the 5 bills. Most audiophiles that have paid so much for their systems can't resist, few can. It's like Church, many listen, few understand. http://roger-russell.com/wire/wire.htm

View Roger Russell's website, many great things, plus tons on cables and wires that nobody can really disagree with (with science). Also his history in the industry (with a decent company from the U.S.A., McIntosh, engineering speakers", his test, then decided if it makes you feel better to blow the 5 bills, you will hear something (and many will tell you their wife even heard the difference, a common old audio line). Most audiophiles that have paid so much for their systems can't resist, few can. Speaker wire is like Church, many listen, few understand. My father worked on Mercury, Gemini, and Apollo, and laughed his rear off when I asked him about expensive cables.