I have a 79 Dakota. I would love to put in an EDM. Problem is what is the difference between the 900 and 930, besides a couple thousand dollars and the screen size? I have the perfect spot on my panel for one of these since I did the ADS-B update last year with putting in a GTN-650 and a 345txp. Any suggestions on which is better? Or is there a better product that is STCd to replace my old gauges?