As pretty much everyone else has said, you have some issues with this setup. The factory "premium" stereo uses a factory amplifier with a built in crossover. So with the way that you are wired up you are not even getting full signal to your crossover that came with your components. And as Crutchfield and others have said the factory amplifier is not really capable of pushing those speakers very well. It's roughly 45 watt per channel at 2 ohm. Your speakers are 4 ohm so they are seeing about half of that, maybe 22 or so, and need quite a bit more. There are a few of us that are limping the factory system along with decent results, but we have used JBL, Infinity, or Kicker speakers as they are low ohm, efficient speakers. But those Focals will sound better once properly powered.I went through this thread at least twice, I am actually doing it now again and I am still lost I added the knee panal speakers Focal ICU 100 using the provided Harness and the Focal ES 100 using the crossovers provided in the soundbar taping into the main speaker line in to the crossovers. And a total disappointment very low sound. So I contacted Crutchfield to try to figure it out I was told that my factory Amp is not strong enough, 2 ohm versus 4 ohm, something like that. It sounds like they might be directing me wrong. Help, is it something that I can do or is it not possible with the factory 8.4. I see a lot of people changing their speakers, I don't see why it didn't not work. Do I have to change them to something else. This is kind of a basic swap I thought I am not doing anything like what some of you guys are doing. Please someone can direct me or give advice. if need I can try to elaborate.