I have a feeling the shudder could be caused by the materal used on the clutch plate, I come to this conclusion because when I first purchased my car, it had a stock clutch and it shuddered when cold. I immediately changed to a rebuilt "performance" clutch (I was still new to the WRX world then) and within about 6 months, the shudder came back. I could start the car in second gear, ride the crap out of the clutch and it would fix it for a few weeks but that really isn't a viable long term fix. I then upgraded to an exedy sports organic clutch- completely new clutch plate, pressure plate and bearings. It's been over a year and the shudder has never been an issue, grabs extremely well and drives like a normal standard clutch.

Hope this helps,

Darren

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