I cam across these in truckin'. they are shaped like the magnapacks. anybody know anything about these? the only reason im asking is because they have adjustable
backpressure/airflow. there is a **** on the side of the muffler that has 6 positions. they look pretty cool, maybe ill try them out.

thanks
joe

p.s.
our tubing is 2-1/2 inch right?

 

Yes, 2.5".