You are in luck.
Go to
www.jettengineering.com
Click on hangar sale.
Follow the page down, and you will see a complete Sport Jett .46 engine (with throttle) for $220. This includes the tuned muffler.
This is a great sport engine that will take the plane over 150 mph. Or, you can cruise around the sky at 1/2 throttle at 100mph.