Im inthe process of building mine. The zdz 40 rear exhaust with inverted pitts muffler was one of my choices. I am however using a Moki 2.10 since I have a new one sitting in the shop. The prototype had a zdz 40 side exhaust ,the muffler required some minor grinding to fit. Hope this helps Apparently the zdz 40 was excellent power match for full acrobatics.