Welcome to the forums Spyder! First of all, if you're going to use a distribuitor for both the + and GND, you really should use same AWG wires. I don't know about your amp and how much power it draws, but the Opus 150W needs a 12 AWG wire, so I'm only guessing the 90W version needs even less. You can place the switch on the remote line of the Opus, and not the main power lead. The only concern I have with your setup is power. I'm not sure that the 90W version can handle a 2G CPU, with graphics, monitor, dvd and usb soundcard, although the last ones don't draw a lot of power. When you say amp thump I'm assuming you mean the buzz when the computer starts, right? Well this only happens if the computer starts before the amp starts, wich in Opus's case that has a delay about 5 second after the remote has been switched on (mine does) is a sure thing. There is a circuit for this, I don't remember exactly but do a search on Jeff Mucha.