The GPS was one of the big let downs with the STX 550 for me. I comes down to two things, updates and no map over speed alarm.
Before I purchased the vehicle I was told by Nissan Sales that the GPS updates itself automatically. At first service I found out the truth about the update cost when I asked for a GPS update quote ($600). I asked Nissan to justify this cost when compared to others like Tom Tom with lifelong updates - no response.
Overall the GPS navigator is good but:
1/ only if regular updates are applied (2 years apart & $600.00)
2/ It gets confused where there are many streets and turns in a tight area.
3/ No map over-speed alerts.
People ask why I use a Tom Tom stuck on the windscreen of a $60,000 vehicle that has an integrated GPS.
If there was a plugin module that would fix this issue I would support it too.