I have them and I'm happy to say that all the knocking went away after fitment. nicer to give it the beans also
Recently a friend drove my car and he said it definitely feels more responsive if not even a little quicker than his- he's got a 172
I managed to keep up very closely with another guy's 182 which had full exhaust (inc de-cat), remap, matched inlets plus ported inlet holes on cylinder head and pipercross venom, rear seats also stripped of while mine had the milltek, no de-cat, the BMC CDA, no remap, rear seats on and a 182 alloy spare wheel inside the boot plus some other stuff
maybe the k-tec mounts helped me a bit who knows? he was about 5 meters ahead at the quarter mile mark