2004 G35 6MT vs 5 AT- engine noise
 

I picked up my new MT last week and dropped it off for a redo on the detail wax job. My 1995 audi had a smoother finish than my brand new G. In driving the 2004 AT loaner, the engine noise was distinctly lower on acceleration. Is that normal and part of the more sporty nature of the 6mt?

I think what you are hearing is the transmission noise in the 6MT. You will audibly hear a manual gear box more so than a slush box.