Swapping factory amp and have a question

For those of you that swapped out the factory amp with an upgrade, and kept the stock head unit, how do the dash speakers sound?

I upgraded all my speakers (dash included but I disconnected the center) and added a powered sub, which is ok but I wanted a little more. Came across a buddy getting rid of a 4 channel amp, so I bought a LC7i and the harness needed to integrate everything. I'm second guessing the dash speakers since they are powered off the head unit.

Any insight from people who have done it already is appreciated!

 

I have an aftermarket HU, Alpine amp, and Focal door speakers.
I put a good set of Focals components in my front doors (tweeter in the door sail) and ended up disconnecting all 3 dash speakers.

 

I just went on crutchfield to see a sale on a head unit I was looking at, and pulled the trigger on it. Not dealing with trying to tune in the amp with the LOC, so I sent it back.

So, nevermind