Originally Posted by LightWerkz
I run the stock calipers with the PFC and havent had any trouble yet. More than adequate for HPDE (20-25 mins sessions) if you are using the brakes properly. BBK would be nice, but not necessary.
+1 and I have a BBK.
Good set of pads, Motul 600 brake fluid (flushed regularly), SS lines and you should be set. No need for BBK unless you track hard and alot.
As the others have said the shuddering you are feeling is pad material on your rotors.