Consider the IVO IFA. Don (KitFox2009 from Vernon) has one in his Model V on an 80hp 912. I have one on my Model IV round nose with an 80hp 912. I am happy with mine and I am sure Don is happy with his. It is a great way to get the 100hp performance without going to a new motor and you may be able to find a used one for a reasonable price. Good performance at a reasonable price. Not the latest and greatest but a very good performer on a bit of a budget.