I need to punch a door opening between my garage and my utility room, it is
a 4" concrete wall with 2x4 studs on both sides and 3/8" drywall. This
makes the total width of the wall almost 12 inches. Do I frame the door
like a normal interior door?

In other words, do I knock out the concrete block all the way to the ceiling
and then frame in the header and then put 2x12s above the header to the top
plate? or do I leave a section of concrete block above? Logic tells me
better to knock it out all the way so I can construct the support better?

The other question is should I do something different with a wall this
thick? It has to be this thick due to the amount of rigid electrical
conduits, plumbing and water supply lines that goes onto both sides of the
wall.

Thanks in advance,

MC