OCC and Litz wires - Furutech Alfa series, Neotech, Cardas

I would like to upgrade current loudspeaker cables which are OFC type (Van Damme 2 x 4 mm2 LC - OFC total definition directional loudspeaker cable)

aim Is neutral sound, fast tight bass

I would like to know your Impression recommendation about following OCC and litz wires

- Furutech Alfa series - using Alfa OCC copper

Alfa S14 (15 AWG / 2x1.4 mm2), Alfa S25 (13 AWG / 2x2.5 mm2), Alfa 36 (12 AWG / 2x3.3 mm)

does anyone know why Alfa 36 Is cheaper than Alfa S25

- Neotech STDCT 12 Hook Up wire - 12 AWG or 3.3 mm2 UP OCC PTFE

- Kabusa Spiral Voice speaker cable using Cardas 2 x 11.5 AWG ultra pure copper litz wire