Hello,

For people who are looking for a simple and straight-forward car amplifier solution: look here.
They charge a huge amount for transport costs but if you are in need ....
Products are not that expensive, for example if you take the 4x40W amplifier module, the used IC already costs between 7 and 10 EUROS (almost 35-50% of the cost of the entire module).

Success!!
Putput