im saying he should run the coils in parallel and then he can ether run them channel to channel and have them at 2ohms or bridge them to 1ohm with ease and wont have to mess around with rewiring
what is your cars make and model, what is the amp make and model and subs. if you know your alternators amperage out put that will help with your question.
ideally you want to be hitting that 35v each bass note but you need to insure that you have proper charging to the bat in your system to make sure you do not drop low voltage. i also suggest you install a volt meter in your car
if i where you man id really relive my past and go all new from scratch. there is some killer deals on tvs for cheap and with the din space you have i suggest a nice in dash tv 7.5-9 inch screen that will hook up to your gps or allow you to get gps on it and not get hassled about it by police...