Wat?!? That's pure unadulterated V8 sound, not some fartbox cans on a ricegrinding 4 cylinder!
It doesn't look like he spent much money on anything outside of the engine (obviously not on door latches or seat belts). Straight pipes or cutouts are cheap and add some HP, but get rather annoying on a daily driver. With the condition of that car, I would assume he just has rusted out pipes or took a sawzall to it.
I can appreciate vehicles with no mufflers and a aggressive cam, when on the track, but it gets tiresome being around them while sitting in rush hour traffic. It also kinda depends on the car. Sitting next to a supercar and hearing a $100K+ running next to you, is much more tolerable than that jacked up truck with glass packs or a civic with just about anything other than stock exhaust.
A mid 70s Camaro is a decent base to set up a fast drag racing car and can still look like it is street legal enough to drive it back and forth to the track (instead of needing a truck and trailer).