sound deadening, coaxials vs components

Currently Installed

Sony CDX-GT200 Deck
https://sm.crutchfield.com/S-fYXdiEMMdP7/App/Product/Item/Main.aspx?i=158GT200&tp=5685&tab=features_and_specs

Alpine SPS-57C2 Front
https://www.crutchfield.com/S-re0F43MfFOO/App/Product/Item/Main.aspx?g=51900&i=500SPS57C2&c=3&tp=93&tab=features_and_specs

Pioneer TS-A6881R Back
https://www.crutchfield.com/S-cIppmdHzCmm/App/Product/Item/Main.aspx?i=130TSA6881&tp=92&tab=features_and_specs

I'm installing a MTX Thunderform behind the seats. I want more upfront bass but my main concern is distortion at high volumes. I'm going to RAAMmat & Ensolite both panels of the doors. Move my alpines to the back, they aren't the best but my back seats cover the rear speakers so you don't get much sound out of them anyways. But where to go from here is my problem.

Should I get a nice set of coaxials or a decent set of components?
Is the distortion coming from the deck or the speakers?
Should I replace the deck or install an amp?

Any help you can offer would be greatly appreciated. This is a big purchase for me and I don't wanna love it up by getting the wrong stuff.

I personally perfer components over coaxial... I like the seperation... I would start by adding a 4ch amp... that will help you with clarity, (as long as it is a good amp) from there I would adjust what eq features you have on the HU... also another factor you will have to deal with if you add an amp is gain levels... that will also cause distortion... I would also look into some sort of external eq if you want to keep that HU... If you want to replace it, find something with a good sized graphic or parametric eq built in... That will help with your clarity as well...

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...don't crush the weasel...