Rotax make a good power plant, mind you they have spalled lifters and all sorts of things happen too, so its not the be all of engine reliability. I have a gut feeling they are not quite as reliable as the Lycoming, and that will be contrary to some opinions here. But in our part of the world we see a lot of Rotax action and I have ...err...good information intel. But I must stress the result is I have a gut feeling that the Rotax is not any better. So lets just say its near enough to be a wash between the two.
The engine weights might be different, but what is the BEW of the two aircraft options as the Rotax has some accessory weight that may or may not be in the numbers, so installed BEW of the complete thing matter.
As for the avionics
Dynon Avionics - Home
They use the D180 classic panel. A very good choice.