The GRT SX has builtin AHRS, Magnetometer and GPS, the only other box is the engine monitor. The engine monitor (EIS) has a small screen which can be panel mounted or hidden and is interfaced with the EFIS. All this for about $4000 with a 8.4" EFIS, that includes wiring and 4 cyl probes.
What Dynon do you have? When I've looked at Dynon it says I need a Magnetometer, engine monior and a AHRS.........sounds like I'm not looking at the right thing.