2013 accord wiring

I have a 2013 accord ex-l v6 im looking to put a fibtl 15 in a ported box with a hifonics 2500.1d amp. I want to keep my factory radio and dual screen setup because there are a lot of features on there that i use often. What are most people running there 12v switched remote wire off of ? someone said use the rear defrost in the fuse panel. My brother had a system in his accord someone installed and they fried his screens and part of the dash. definitely something im trying to avoid.

also do you think if i run my stock 135amp alt and throw an extra audio battery in the trunk ill be able to power that amp without dropping voltage too much? ill be using all knukonceptz wiring. Been out of the audio world for about 5 years. thanks