Hi, I have the original stock GPSMap 520 in the dash of my 2008 Cobalt 302. I want to upgrade without hacking things up too badly. The replacement for my 520 is the "547xs", which is actually smaller than the older 500 series units. I found a 546s (NMEA 2000 compatible) for sale. Any suggestions besides putting the newer 546s unit in (which will fit exactly). I also have the dual binnacle DTS, and was wondering if I could plug into an NMEA 2000 GPS, and get engine RPM, etc.
I can't answer your question about which unit to purchase, but yes, you can plug into a NMEA 2000 system and get engine info. I owned a 2008 Sea Ray with DTS and was able to get engine info via NMEA.