I have .46, (2) .53, (5) .80, R120. They are great. The only down side is you can't reach the plug when the engine is running. They come with a remote glow hookup which allows me to hide the connection instead of making a big hole in the cowl. I never worry about the prop arc as that hookup is several inches back. I have two Saitos and a YS. I watch for sales on Enyas first.