Thanks for the info - I'll do a search on the regulator.

As for the acceleration - what you describe seems to fit my description pretty accurately. All I can say is YUCK! Heavy acceleration is not very smooth at all, nothing like my M103. I had no idea there would be such a night-and-day difference between the two engines. My M103 will sing all the way to redline, whereas the M104 sounds like a blender under the hood and won't hang out in the upper RPMs for very long. And this is improvement?

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280