Hello, I’m sure the question has already been asked here, but I haven’t found what exactly I need. To my audio system: I’ve installed the RCD310 with 4 speakers at the front and 4 at the back. I’d like to upgrade the bass a little bit now, as this is known to be rather weak. I’ve read that I need a power amp plus sub. I’d like to build the sub under the driver’s seat and the power amp under the passenger’s seat. i 8 loudspeakers + sub need exactly for a power amplifier. So how many channels? Don’t get through there somehow. I would like to buy the stuff at Ebay so it doesn’t get quite as expensive. So I would need the power amplifier (how many channels anyway?) and the sub (have picked out one of Pioneer, who has quite good ratings), then I would need a high-low adapter to connect the power amplifier to the radio and still cables to bring the sub to the power amplifier correctly? I don’t need a high-end device, I just want to relieve the speakers from the bass. A good middle thing I would need. What can you recommend? It would be very nice if someone could help me on the fast ones. LG Joe