I drive a 2015 Hilux, and one of the things that bothers me about it is how loud it is inside the cabin, as well as the poor quality of the audio, probably a combination of poor insulation plus not so good speakers. I mean, the doors on this pickup are the lightest I can remember on any vehicle, so they probably don't have an ounce of material dedicated to this purpose.
I've seen quite a few videos on how to sound deaden a car, even this one on the exact same model:
Trouble is: I live in Brazil and I don't seem to be able to find the materials used on the video, and if I find something similar the costs are way too high.
Also, I've driven quite a few cars that have from stock a much better insulation and audio quality, but don't have nearly as much done on them as they did on the video, like for example a 2018 Ford Ranger I drive at work or a 2012 Cruze I just recently sold.
So my question is: what would I have to do to bring the Hilux up to the standards of an okay stock car in terms of noise and audio quality? Would it be enough if I just stuck some bitumen deadening material to the skins of the doors, or there are other measures missing from the Hilux? I doesn't even need to be amazing, just bringing it up to where the Cruze and the Ranger are would already be more than enough.