That’s marketing to sell more exhausts. If no remapping is needed, then they don’t provide any improvement over stock either.
ANY change to system that’s benefical, as in providing more airflow, REQUIRES remapping ECU. There’s no way around laws of physics, more power require more airflow, and more air requires more fuel. Even with stock exhaust, remapping ECU on dyno will give you +10% more power as well. However, many of adjustments are in opposite directions. Typically you add more fuel in high-end/high-load areas of map, yet need to remove fuel in mid-range/low-load areas.
Yes, remapping factory ECU is best solution. Here’s software that will let you do it. Still need dyno to determine which way to adjust every single data point on 3D map. Best to find eddy-current load-dyno that can hold engine at each LOADxRPM location on map to get accurate AFR reading. Every single bike is different with different manufacturing tolerances and different levels of wear and tear. Pre-made “flash” maps or maps from other bikes will not be optimised for your bike.
https://www.woolichracing.com/produc...-flashing.aspx