I wouldnt worry about the gauge. On MDS equipped motors, the gauge will actually display real time oil pressure readings. At speed, it is normal to be above the middle mark and below at idle. This is different from non mds trucks, as their gauges are dummy gauges that read in the middle at all times. This is doen just to recognize that the motor has atleast some pressure, but does not tell how much. The real time gauges are installed on MDS trucks, as I believe it has to correlate with the fact that oil pressure plays a role in how the MDS actually functions.

Now, as far as the oil on the top of the motor, that is a different story. Check gaskets, ie intake and valve cover. Was it overfilled by chance? I will continue to brainstorm, but I do not believe that it was caused by excessive pressure, as the gauge was reading near normal, based on RPM when warm. It will read higher at all speeds when the engine is cold, as the oil is still thick and unwarmed.

 

Also, no worries with the moisture on the cap, as long as its not heavy dripping water. This is normal for this motor, as all of the 4 hemis ive had have had this. The cap will be stained. No worries there, as long as the oil in the motor does not look like a milk shake, signifying a cracked head or leaky head gasket. No big deal im sure. Drive it like you stole it