will like an opinion or 2

in the process of building my carputer.
was thinking of going all the way to keep signals digital till the amp level
that meants getting amps with digital inputs
however, i notice the choices are really limited

Alpine V12-AccuClass D series MRA-D550 (5 channel)

Pioneer RS-A9
Pioneer RS-A7
both 4 channel, A7 has 2 optical in

and a prototype product which doesn't seemed to be on market
Pulsus Tech 6 channel amp http://www.pulsustech.com/ref/ref_tbk.html

does anyone has experience with any of these?