When I slowly let out on the clutch in 1st I get a shutter/vibration. It didn't do this until recently after I just replaced my clutch in my 04 wrx. Since I picked the car up from the shop Ive been having trouble with sputtering and vibration letting when I let the clutch out and downshifting. The only way to avoid taking off with out this going on is reving around 2grand and letting out yet it doesn't seem to do this when it's cold in the morning until the car starts warming up. I asked figured something with the clutch installation, but the guy from the shop insists it's not becuase it being a hyrdolic clutch. Could it be bad motor mount, etc., or is it the clutch and the guy is just being ignorant or stubborn? Any sure way to tell what's going on? Please helpp!!!!