[NewArt]

Just back from a 2 day event at Mont Tremblant, fantastic weather and a huge amount of fun! Car (2004 Boxster S) ran well with no problems except: brakes...
At my last event in May, I noticed that when my brakes gor hot, say after 3 or 4 laps, I would get major vibration through the steering wheel. The rotors were Meyles all around. I changed the front rotors for some Zimmermanns, after having cleaned and sanded the hubs. I then seasoned them acourding to Hoyle. I also installed the GT3 air ducts. I have received some new pads (EBC Yellowstuff) but didn't have time to bed them for this event so I ran with my Redstuff pads which still had lots of legs. Unfortunately, the shimmy persisted. I will be installing the Yellowstuff pads in the next day or so.
Is it possible/usual for a brake pad to cause this juddering problem?