Learn the SIMPLE steps required to sound proof a car. I spent about $130 on materials and tools but could've done it for even less (skip the foam layer). On a scale of 1-10, if this car was a '1' and a luxury car is a '10', the car is now a 5 or 6.
Here are the products I used:
1) Sound-deadening foil panels: www.amazon.com/dp/B07B75TBCV?... (paid link)
2) Sound-deadening foam: amzn.to/43TaWUG (paid link)
3) Rollers: amzn.to/3X32LCL (paid link)