99 Gs400 stock nav with clarion tv tuner in the rear with two headrest monitors dvd and sega dreamcast.

question do i still need gex 7000 to make my conversion work or can i use the clarion unit instead as long as i buy everything else i need.

You still need to get the GEX because the RGB cable that hook up to the PBA-V1 only accept the Pioneer RGB 20 pins cable.