So I have my amp wired to my stock system using an impedance matcher with rca stepdowns, my question is... The box that contains the impedance adapter has two dials on it that are adjustable, plugged in, it works fine now, but I don't know if they need to be adjusted for better sound or performance. I know that it won't sound anywhere near a good HU, but will changing those dials do anything? Here is the link...
http://cgi.ebay.com/HP-Audio-2-Chann...QQcmdZViewItem

 

you can turn it up to the max, it will give more voltage out to the rcas, but its only going to give so much. the best thing is get a headunit with 5volt preouts