does it make a difference using 10 gauge speaker wire and 14, as far as performance goes?

running to L7s off a kicker 1500.1

well 14 gauge can support 32amps of current and at 1ohm that is about 1024watts

and 10 gauge can support 55amps of current and at 1ohm that is about 3025watts

but that amp is a 2ohm amp so the new numbers are lol

14gauge at 32amps and 2ohm = 2048

10gauge at 55amps and 2ohm = 6050

reference formula

~~~~~~~~~~~~~~

I^2XR= Power

(current squared times resistance = power)

that tells me everything

It wont matter but if you already have 14gauge then use and dont go out and buy 10 gauge unless you want to (speaker wire size will come down to personal preference, some use 8 guage but is it over kill? YES).

does it make a difference using 10 gauge speaker wire and 14, as far as performance goes?

No, it won't.