Allen's 1 day LTH install 

It's backfire along with lost of backpressure caused by no real muffler or resonators in this setup. Once he realises the throttle air is somewhat sucked back through the system "blowback" causing a horrible hiss. I may be explaining it wrong but yeah...something like that lol

did you get any check engine light problems?

haha what was that sound at :58?

ppe > obx