R&R flex pipe

No laws on flex pipe but they are used to span moving parts. Like air ride cab and frame. They do help with taking out harmonic vibration from exhaust pulses. Thats why some oems use a piece close to the turbo. If cab, engine, and pipe is solid mounted like the old pre- air ride cab trucks then flex is not needed. Flex also just plain makes tight spot bends and turns in some systems much easier to run.

 

$18 on Amazon

 

This works way better than the muffler cement