The Sound of Cars is producing interesting video comparison of classic rock with period cars. Episode four compares Porsche's impact bumper introduction in 1974 to Led Zeppelin's Houses of the Holy. For this episode, the producer mixes his two passions into a single theme that compares and contrasts how both shocked their respective fan base, while also being pivotal in setting a new course. Some of his thoughts include "just because the eyes of the people back then couldn't process the new look, didn't make it any less of a car". "[Porsche] knew they couldn't make another long hood pre-1973-style car. Too many laws had changed from emissions to crash standards. So they took the car they came up with for 1974 and made the best damn car they could. For 15 years the impact bumper lived in rarified air as a top-of-the-line sports car that wasn't made in Italy."