Quote Originally Posted by FlyingRon View Post
That still leaves him without a legal navigation source. The GNX375 is not approved for IFR use in certificated aircraft.
It most certainly is. See:

https://buy.garmin.com/en-US/US/p/577174

Last paragraph on the page says:

"With installation approval available for hundreds of Part 23 Class I/II aircraft models, adding a GNX 375 navigator to your cockpit is a straightforward, all-bases-covered proposition."