I would agree the Mac is lighter and will not fall apart in flight. On the same 46's with the same prop I had no increase in rpm's on either engine. If you want to really get a performance boost at a great price use a Mousse can muffler. Do a search on how to make one. There is a source for complete Mousse cans down in Fla. I cant find to paper. I have one on my webra32 and it screams. At $28 it was a deal. Pete