So next week I’m installing amp & 4 speakers in my ‘18 ultra limited. (MMats 4110 & 601cx). I already have Sony 7000 installed. Wondering if it’s better to run new speaker wire to the rears or just tie in to the factory wiring. I’m assuming the new speakers would be happier with some 14 gauge wire but maybe I’m overthinking it? Is there a plug in the fairing to tie into the rear speakers? I can always tie in to the harness coming out of the Sony.
I appreciate any thoughts & advise

I run new wire. You already have the seat and tank off. The factory wire is thiin.

Run new wire.