I had all four of my speakers running off a phoneix gold amp. Worked well but sounded really good when the back speakers were disconnected. The back speakers were stock and playing louder than the front components. Sounds great now lot better soundstaing but if you jsut want loud 4 speakers is the way to go. It usally easy to get less speakers to sound better. Wouldn't need a cap for a small 2 channel and could run power from one amp to the other and same with the rcas and would only use a short rca provided there are the proper crossovers in the amps. Just a suggestion.