Well this is an old thread but I thought I would resurrect it as I finally solved my clutch problems. Obviously my main issue was the clutch replacement itself that was done immediately. As mentioned in earlier posts this got rid of the stiff feeling "mostly". However I finally had the dealer replace the Clutch Helper Spring which is connected to the pedal in the driver footwell. Removing, relubricating, and replacing with a new spring made the clutch how it should be. I can only assume points needed to be cleaned and the spring itself was bad.
Funny thing is I have read in another forum about 996 owners removing the helper spring altogether...which is how mine "felt" being bad. Reason: It is harder to press but you can feel the clutch engagement point a lot better. Useful for tracking or fun driving, not so fun in stop and go traffic. All I can say is I can understand as my clutch is so easy now it is like butter and I practically have to learn how to re-shift / go slower-easier on the pedal hehe.
My car now has 51k miles and with the original clutch replacement/LN upgrade and now the helper spring it is like new.
Yay.
comet