Are these excessively noisy on the highway? Also, has anyone got any thoughts on the 70 series? Thanks in advance.

 

My 50 isn't loud on the highway, but still gives a nice note. At idle, the gives off a good sound. When you get on the throttle, it really comes alive, sounds awsome. It's not the delta flow though, whick delta would make it quiter. The 70 would be even quiter.

 

Quite at highway speeds. Not loud, but you can tell it's there. Sounds good at idle and during acceleration.