I believe they make a unit with those that uses the power stack amp as well.
I like it because you don't have to find another spot for the amp. It all fits in the dash.
They do! https://www.crutchfield.com/p_500ILX407/Alpine-iLX-407.html for $450
$200 for the amp stand alone https://www.crutchfield.com/p_500KTA200M/Alpine-KTA-200M-Power-Pack.html
And HU bundled with the amp https://www.crutchfield.com/p_700407200/Alpine-iLX-407-and-Mono-Amp-Package.html for $665
This is good food for thought. Thank you.