[Info@mad-us.com]

Most exhausts are going to be more restrictive with the valves closed. Smaller piping diameters sharp angles are never good. You can't really see what's going on in the muffler though so it may or may not be as bad as it looks.

The stock exhaust has a series of walled baffles and some fairly small piping where it enters. At Wot the valves will always open so I guess they figure it doesn't matter.