Problem replacing 6X9s in a car w/ Bose

So I get some nice Kenwood 6X9's hooked up in my boy's 1993 Infiniti Q45 and when I turn the music on they sound like crap.  Not only do they sound like crap, but they aren't as loud as the stock 6X9's and they make an interference/humming noise when the amp is hooked up.  I'll try to explain how the system is set up. 

 [b]With all stock speakers:[/b]

 [b]When the Kenwood 6X9's are in:[/b]

So will he have to get a new HU and do a full bypass to be able to add new speakers?

You're right about the speakers-those are amps on them.  The thing about Bose is they operate at a lower resistance (usually 1 or 2 ohms), and the amps are set up to push them.  So when you hook up a 4 ohm speaker, they will play at lower volume and have slight distortion.  Usually when something goes bad in a bose equipped car, you end up changing the whole system and running new wires. 

The humming you hear is probably a ground loop going throught stock amps and getting transfered to the sub amp and the to the sub itself.  You can probably stop it (i think) by grounding the sub amp at the negative side of the battery but the won't solve the speaker problem.  Easiset thing to do is get an aftermarket head unit/speakers and run new wires. 

Hope that helps

Duane...

If you think you're confused, imagine how you feel.