Just did a 2003 RSX Type S last night.. dropping a line to make it easier for anyone else to follow. Put in an amp and sub combo off the factory Bose system. on this car, the bose amp was mounted under the passenger seat, actually suspended from the seat. there are 2 10 mills holding it in place. For the remote turn on, there's a relay mounted under the amp with a white wire. This is the wire that kicks the bose amp on, and is the normally open connection on the relay. easy to tag into. The speaker lines (of course) were harder to find. I found the rear speakers in opposite corners of the plug. The (man i forget if it was right or left) one was a blue w/white and blue w/black set, and the other was in the opposite corner (as in if you hold the plug so the b w/w and the b w/b are in the upper right corner of the plug, the other rear set is in the lower left corner. It's a pink and a blue set IIRC (the pair was semi twisted back in the split loom). run a line level converter off of this set. The other option for the speaker lines for just a sub would be off the sub in the rear, but there isn't a remote turn on back there. it seems as if all 4 of the wires are audio, even though 2 are larger like the other bose use for power lines.

 

Thanks for the info!