I've done that. When I first realized the truck spurs were faster I switched over via one of the service areas. However, I have only driven in the cars spur since after a piece of cargo/degree came loose from a truck and came flying into my windshield, cracking it.
I'm gonna take a moment to clarify some terminology (which probably will probably nitpick, but this is what I know them as)...
The "spurs" specifically refer to the split roadways north of Newark, where one branch goes east of downtown Secaucus and the other goes west. These are the eastern and western spurs. (history lesson: The eastern spur was the original built in 1952, the western was built in 1971).
From Newark south to Exit 6, its just the "car lanes' and the "truck lanes" (officially just referred to as the inner and outer roadways).
Then there's the Newark Bay-Hudson County Extension (I-78) and the Pennsylvania Extension (the I-95 link to Philly and the PA Turnpike).