I been trying to figure out what upgrades I wanted to do and then I found this website and thought who better to ask. I have a bone stock 2006 TRX400EX. I like the quad but want a little more power. I have read bad things about the 440 kit so I was thinking about the 426 with a cam and intake and exhaust along with an upgraded CDI. Since this is my first quad that I am thinking about breaking down the engine I would like some input from others. Also thought about building the engine for strength and adding turbo. I grew up riding motocross bikes but now have a wife, 2 children, and have beat myself up enough I enjoy the comforts of the quad. The other solution is to sell and get a bigger quad but really like the Honda name and I got this for a screaming deal. Is the 450 that much better? Thanks for any input.