i have an 03 coupe with the bose system..no navi...i have an infinity 4/400 amp...how do i go about replacing the factory amp...do i leave it in or take it out....also i have the alpine iva-d310 with the brain underneath my passenger seat....i know that i run my rca's to the amp from the brain but is there anything else i have to do with the factory amp such as the two harnesses that come off of the factory one..? thanks

 

from the aftermarket amp you have 2 options. run new speaker wire. OR splice into the output side of the amp to send the signal to the speakers.
you're bypassing the factory amp by doing this

 

alright thanks....ill be trying this soon...if i run into anymore questions ill post em..thanks!