If the car is in neutral with clutch fully disengaged, you should not be experiencing the idle drops. It is not the clutch. So.....
-Check to see if your throttle body is clean
-Check the MAF ground wire
-Make sure your plugs, wires, cap and rotor are in good shape
-Check the EGR and make sure it's not clogged
-Check your base idle and
-Check your timing
That should cover all the bases. Most of the procedures can be found on
www.se-r.net or you could search the forum and see if they are posted.
Hope this helps!