I have a old MDS, but since it is so noisy, (about 0.9 cox'es) I tried to muffle it a bit with items commonly found floating around in my buddy's car!
First I tried a plastic bottle. Cutted out holes to the exhaust tube and the exhaust exit. During the test it worked very good!
....But after about 5 minutes of flying, the MDS started to run weaker and even more silent. The plastic bottle melted and muffled it more than it could take.
Then I found an empty startgas spraycan. It was a bit harder to cut out the holes, but it worked vell, apart from making the cub fly like in a constant crosswind.