The difference between Stage 1 MMC and stock pipes is pretty dramatic. Stage 1 is loud, especially on acceleration in the lower gears.
The best part of them is the lower end smoothness. Not sure if that is a function of the air cleaner Venturi treatment or the exhaust.
I would hazard that it is more air in
I thought so too, but the air cleaner is larger in the oem filter, much larger, the venturi stinger is the main difference but it has a smaller air cleaner surface.
2019 M3W Sold and is now in Las Vegas enjoying the showgirls :-)