As another poster said, the GRT EIS has been around for a long time, is reliable, has everything you’ll need in an engine monitor and couples to other GRT EFIS equipment. You could buy a GRT Mini-X for $1395., and it will display all engine info in a very readable format that is also a PFD/mini efis (if you want to select that page)with its internal AHRS, moving map (if you want to select that page) with its internal WAAS GPS, and has the option of a built in backup battery. The EIS module can be the remote unit, or the panel mounted, both of which communicates with the Mini via a single RS232 22 gauge wire. There’s a lot of bang for the buck with that arrangement.
RV6/2001 built/sold 2005
RV8 Fastback/2008 built/sold 2015
RV4/bought 2019 Flying