i understand i need something that converts my stock HU to rca for the input of the empeg. how many of these converters do i need. whats with this rear and front rca plugs if the empeg only has one set of inputs. how is that handled? it outputs in these 4 correct?

You only need one of these converters. They come in 2 or 4 channel varieties, but since (as you pointed out) there is only a two channel input on the empeg, you only need the two channel version. Just set your fade to 0 on your head unit and then pick either the front or rear pair of outputs from your head unit and cap off the other pair. Then connect the right positive and negative and the left positive and nevative to the correct wires in the adapter (they should be clearly labeled.)

The Empeg does have 4 outputs but the output is still stereo, not 4 discreet channels. The four outputs just allow you to adjust the front/rear fade.

Something I didn't think of earlier is to check to make sure your car doesn't have an OEM external amp (some include them from the factory, esp. with premium sound systems). If it does, then you won't want to use a line-out converter.

Edit: The bot beat me to it ...some of this info is duplicated...