The recommended spark plug gap for all emission controlled engines is listed on the emission control label in the engine compartment, so there is no need to guess.

For my M103 it is .032" and I believe all other M103s are the same.

H9DCs or DC0s should be gapped at about .032" out of the box, but they should always be checked prior to installation.

The recommended replacement interval is 30K miles for 49-state cars, but MBNA recommended 15K miles for some CA models as a hedge on the emission warranty.

The recommended tightening torque in the M103 engine manual is 20 NM, which is .72(20) = 14.4 lb-ft = 173 in-lb, but I use 150. Most OEMs recommend in the range of 10-15 lb-ft for 14mm taper seat spark plugs in aluminum heads.

Duke