so what you are saying is that its best to run to amps if intending to run a sub, yes/no. if yes is the case, may this be a problem if i only have 2 re outputs on my h/u or does it not have to reply on it. having said that, can i run a second amp say 2 channels to my 4 channel amp in which there are 2 channels free on the 4 channel then just use the additional amp to run the subs. confusing? impossible?