I tried posting this in the AV forum but nobody got back to me, lets try here;

So i'm looking to buy a new head unit on crutchfield, but when i put one in my cart it says "you may also want this" http://www.crutchfield.com/p_127SOEM....html?tp=22564
which to me looks like an amp manager, as in the head unit doesnt have any actual power but each individual speaker has it's own amp like the Bose nissan maximas used to do. Is this true? I just disconnected my tailgate speakers, which had their own amp, is this the case with all the speakers? I'm asking because if i have to side step the amps and run new speaker wire to each door that seriously elongates/complicates my head unit install. I'd appreciate any insight from people who have already done aftermarket head units. I've done them before but not in the Disco. Is there a wiring harness out there thats essentially "plug and play"?

 

There is one amp for the stereo, it is under the glove box, it needs to be bypassed.
I had Best Buy do my stereo and they bypassed the amp, it was toast anyway. (I found out later it is a blown fuse in the amp)
I am getting ready to replace my head unit again with a better one and I will be doing this one since Best Buy no longer does the free install.

 

As far a I know, some factory radios connected with a common ground (one ground for all channels). Aftermarket radios have separate grounds and will not work/blow if you connect them to your stock system. The item seems to be a common-to-floating ground converter that will allow you to connect any aftermarket head unit to the stock system.

 

But there's no need to leave the factory amp in the system if I don't need it right?i feel like it would be better/smarter to just order the head unit with a regular wiring harness, run new speaker wire, splice in the wires and side step the amp. I've run similar set ups in those older nissan maximas and its just a matter of running the new speaker wire through the doors to the new speakers and then splicing them into the harness. God forbid anything should be easy

 

The amplifier can be bypassed and then that harness is not needed. Remember that the subwoofer also acts as a low range speaker.

 

I feel silly as this subject is about the only thing I have posted on, but for what its worth...I kept the factory wiring and amps by using the harness referenced in this thread
*LINK
As stated in that thread I did have to run a new ground off the back of the head unit.
Now it may not be an audiophiles dream, but its pretty decent and I got results I was satisfied with, with very little effort.