You could go with a solid core copper or silver wire. Or a 12 gauge or less stranded copper wire, which too my ears doesn't give more bass. It just attenuates the highs to give you the perception of more bass.
FWIW, the gauge doesn't have a big effect on the bandwith unless run over long distances. The distance will effect the high freqs before it effects the low freqs. If small gauge were a bad thing, all telephone companies would use wire larger than 24 gauge. My speakers internal wiring is 24 gauge solid core copper. The speakers still go well into 20Hz range. Save your money.. try 12 gauge HD wire and see how it works out for you.
FWIW, the gauge doesn't have a big effect on the bandwith unless run over long distances. The distance will effect the high freqs before it effects the low freqs. If small gauge were a bad thing, all telephone companies would use wire larger than 24 gauge. My speakers internal wiring is 24 gauge solid core copper. The speakers still go well into 20Hz range. Save your money.. try 12 gauge HD wire and see how it works out for you.