I like my magnaflow catback but think it makes a weird resonance which is noticeable around 60miles an hour in my car. But if I go a bit faster say 70 mph then it seems to go away. Could this be something else like tires or something but it seems to also be noticeable when you go up past 70 mph and then slow down. I don't notice it at all at slower speeds than 60.
Anyone else notice this with the magnaflow and if you did would say a bullet muffler help with this?