I have the Scangauge E, but I find it pretty limiting with only two "gauges" displayed at a time. I think the regular Scangauge with 4 "gauges" displayed at once would be more useful. I have no experience with the Ultragauge.
You can buy a Scangauge from EcoModder!
https://ecomodder.com/forum/ecomodder-store.php