I just replaced my stock HU with a Kenwood ddx8019. Now if I want to replace the amp and speakers do I need to run any wires to the trunk or can I just splice into the wires going to the Bose amp?

Second question: do I need to buy anything else besides amp and speakers to make this work? Any suggestions for speakers and amps? I don't really feel like adding a sub but I've heard putting subs into the rear deck where they originally are is a bad idea.

 

yes you need to run power, remote, rcas to the amps and new wires to the speakers.

you need everything listed above plus a ground wire and fuse block.

 

Why would i need to run new wires to the speakers and amp? What is wrong with the wire already there?

 

you need to run power and ground and remote wires for the amp. it's just not there in the stock wires. The rcas are needed to get the signal from the deck to the amp, this would get you the best sound quality. another option would be to use a line level converter to convert from the speaker level to rca level inputs of the new amp (or the amp may already have speaker/high level in) but this is a really bad way to do it. You'll end up with more distortion. from the amp the best thing is to run new speaker cables to the speakers, the stock wires are annemic at best maybe 20ga? you should run at least 16ga. going through all the effort of putting in a new system you should go the extra yard and do it right.