Martin,
If you are going to the trouble of changing the ATF, I would change the screen and the fluid in the torque converter. Be sure you use the recommended spark plugs. They are not expensive and problems arise with using resistor plugs on these engines. Don't remember what year this car is but if it has distributors/rotors I sure would take a hard look at them. Unfortunately they are NOT cheap.
Anziani
'97 CL600 53K