I've never seen a post where someone used that big of an engine. Many used the Saito 100 and thought it was great. I loved mine with the Saito 82 and found it to be about perfect. Even with my high elevation. I think the 115 is the same bolt pattern as the 100 so it should fit in easy. But keep in mind the UCDs are not to be flown fast. You may get yourself in trouble if you don't use exceptional throttle control.
thanks
Barry