Well.. if you're gonna go, might as well go big. I doubt anyone will argue your choices. SOS is definitely the best, and Nexus is definitely the cats ass of gauges.
My recommendation is a wideband, a fuel pressure, and a boost
Personally, I have been kicking around the idea of the ProSport gauges myself. Same basic functionality of the Nexus series Autometer gauges, and about a third of the cost.
If I have ONE MORE DAMN FAILURE out of my Autometer Cobalt gauges I am shitcanning all of them and going to try the ProSports.