one of those posts in that german thread, google translated
"Bin the KPJD down before I switched to the FMF! Does the KPJD say that pretty much the loudest is what I have degree are on exhausts! For the roads or racing operation only conditionally recommendable, since it is way too loud to ride it for location! Also it also does not bring the torque which brings an FMF! The KPJD brings almost only speed! Can you just advise against it, especially when it comes to the topic of volume!"