any one here wit a cls has got they cylinder head port n polish b4 wit all angle n value job>?

 

The only one I remember reading about lost power. Not sure if its going to help unless you plan to go FI. Maybe the guy who did the job just didn't know what he was doing, but that post alone would scare me from doing it until I read about someone else who did it right.

 

i think porting would be a good option only if you are planning on installing a s/c otherwise you wont have the needed airflow to push the larger volume of air through the larger volume in the head and this is why you see a drop in performance (i think)