Buy (2) or more ZDZ 50 NG's with pitts mufflers. $625 shipped each. You have to talk to someone there and ask for the price. They don't advertise it. I bought three and Mike threw in the prop drill jig. All this for $1875 shipped. That's over a $100 savings on each engine when you include the free prop jig and free shipping.

http://www.rcshowcase.com/html/ZDZ/zdz50.html