I currently have the BMW PE v1 exhaust. I find it very quiet, even with the primary cat deleted. I also find it too metallic sounding.
I was wondering what the differences were between these different levels of mods of the original exhaust. I can't find any definitive answers on any forum.
Looking at this picture.
There are 4 areas with vented pipes and 2 Helmholtz resonators.
What is the 2 vs 4 pipe mod?
What makes the x.5 version?
Thanks