Good luck with this one for an Euopean registered certified aircraft. It seems to be the current Dynon position not to seek certification under the EASA regime. Of course you can try to validate the US STC within the EASA framework on your own, but that is not an easy one.
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It is my understanding that Dyon lists the name of the prospect installer named by the buyer in the STC paperwork. So you better talk to Dynon first if they are willing to approve an Euopean installer for a certified aircraft installation. Only if this first hurdle has been taken, it makes sense to look for an installer.