It's been a while, so i'll try to make it worthy.
Today removed catalytic convertor and replaced it with a pair of resonators.
It sounds great, not louder than febore, idles much better, smoother take offs and even smoother rev downs.,
it also helps quiet rattlening/lightened fly wheel.
muffler: Supersprint # 892406, catback with X pipe.
headers: Supersprint # 782101 type, they are ebay copy's with X pipe
Catalytic: Supersprint # 043203 type, my version of SS e30 m3 "centre catless section"