With the engine sitting on its side and other things in the way, not sure if something off the shelf would fit, also depends on cowling space. I don't follow the developments too much on these engines any more since Jan does not allow people to participate on his forum very freely.
If I recall there were some crankcase breather redesigns and something in the gearboxes. There were also numerous issues with their ECU, especially with cold starting. I believe they had at least 4 iterations of those.
We have sold a few ECUs to dissatisfied Viking owners and quite a number more to other Fit users who are doing their own conversions. The engines are quite popular in the 100hp range these days.
The latest Viking engines stand upright and have the factory direct injection in place I believe. Not sure what ECU they use to control that.
The basic Honda Fit engine is very sound but all the new systems added to the outside need to be reliable to make the whole package so.
There was not enough testing (as usual) on the early engine packages before they were released for sale, hence a number of issues quickly came to light.