I also have the same problems with vertical wavey lines when plugged into the onboard VGA, when i use a PCI card there is no problem at all.
I also tried it with a regular 19" LCD screen from my computer, same problems with the onboard VGA..
Been searching a while, in my case i wanted to buy the 5200FX to solve this problem, but if there is a solution to use the onboard VGA without any noise that would be awesome.
I have tried various VGA cables, shielded, gold plated etc.. but it doesn't seem to help fixing this problem, im sure it has something to do with the onboard VGA connector.. at the moment im just connected to a regular ATX power supply at home for testing before installation in my WRX... Though i think when using the M2-ATX psu this problem would not be fixed.. since somebody i know have the same problem with onboard VGA usage.