5N0 uses rSap to connect to the phone, i was reading somewhere the other day that other 3g services such as whatsapp and internet etc didn't work all the while the phone was connected to the 5N0 unit, plus your phone and future phones need to be rSap compatable.
The only good thing about 5N0 is it works straight away with red and white displays
if i were you i would go with a standard module like older 5k0 or newer 7P6 and just get the other module from carsystems.pl to use on red display.
much cheaper than 729B which i've had in the past plus newer modules give you audio streaming, like many people i thought i would never need this but with spotify and tune in radio and other streaming apps i constantly use it
a list of all modules can be found here
http://wiki.ross-tech.com/wiki/index.php/Telephone_Retrofitting