Just looked at that Transit again, I really cna not see how that van can hit 170db wise...................unless I have missed something. After 120db every db is like a major stepping stone and after 145db each db it is like 10x harder. There are db drag vehicles out there which do hit 160db but they have way more serious ICE.
Construction, Bespoke Joinery & AV fit out services.
my brother used to do spl with his vw scirocco, using 4 18" subs in a diamond config with 8 1000watt amps he used to hit 156db regularly with a 159db measured in the front footwell....