everything Montague said is exactly correct. the Webra on a muffler with a 2548/LimB prop is a stone. On a mcp with a smaller prop it is a powerhouse. I have had some webras that would not get on the pipe with a 9x4MA and had to clip the tips 1/8" to get the engine on the pipe, it really likes to rev and if it's bogged down it will be doggy. the fuel consumption is very high. even though I love the power i generally prefer the user friendliness and reliability of the FX. I save my webras for Nats when i figure you want all the power you can get. but i'm nervous every time i start them.