Wiper Problem Solved:
 

I discover a connector on the N10-1 Combination Control Module was not fully seated. Once snapped in place, the wipers came back online.

I must have disturbed the connector when removing the DME...:)

What kind of MPG are you seeing with the M104? My dad/bro have been getting 23-24 city (and they are leadfooted) and about 28-30hwy with their M112s....

Wife is getting consistent 28-30 with the M104 and the V6's that I am aware of personally are only getting mid 20's at best. The other thing is, and I am not quite sure how to explain it, but the 112's feel rough to me. You can't even feel our 104 running, you have to look at the tach to see if it is still running and the 112's I have driven just feel unbalanced, if I explained that right.

Now, my 2.5 litre 4 valve, twin cam/VANOS BMW M50TUB25 (straight six) is getting over 30 mpg (30 mpg average over the past 5 tanks of fuel) and it is totally silent, where the M104 does have a sewing machine quality to it when you are under the hood. While doing the bodywork, we once left the BMW idling for 3 days because you couldn't hear it running...

Even with a 4.10:1 gear in the BMW, my wife's M104 is faster off the line, as it should be with more CID, but from 115-up the BMW is faster...

The M112's I've been in have been fairly quiet in the cabin, but they have a rougher quality to them than the M104. They've idled nowhere nearly as smooth as the M104.

But who knows, it could've been motor mounts. Put worn out motor mounts on the M104 or the M113, and you can definitely feel the vibration in the cabin.

90 degree V6 with additional balancer gears will never idle as smooth as an inline 6. you can get the same smoothness in a V if the engine were 60 degrees.

That being said, I have done motor mounts on 112's and 104's and the 104 always feels smoother...I still have to give my BMW M50TUB25 the nod for smoothest and quietest of them all...

Here's an article that describes Mercedes decision to switch from the V6 to a new family of inline engines:

Mercedes-Benz to Replace V6s With Inline Engines Report Says - MSN Autos

Hmmmm....interesting...