"There is no Color Management involved in that process.."
thats not right!.. of course there is.. the printer does the color management as it says..
the built in tables of the Z transfer the color.
"If you print 16 bits files skipping the printer driver, you`ll get best gradients and IQ in your prints. "
thats not right either. you cannot "skip" the printer driver unless you use a RIP.
the PS version of the Z has the ability to apply its color tables to a 16 bit image and THEN calculate it to 8 bits for printing. still prints 8bits!
the normal version cant at all