I have not done the conversion myself, but I was interested in it previously.
When I contacted GoFasters, I was told the following parts are needed...
Minimum Requirements:
- Head
- Cylinder
- Piston & Rings
- Gasket kit
- Reed block spacer (for carb)
The parts above would be in the $1100-$1300 range (with the cylinder being the expensive part).
I also recall that the PV was updated a few years ago. I'm guessing the 2006 and later uses the same one. PV assembly would be in the $180-$200 range.
If your CDI does not have a dual switch capability, then this is another option that you can add to get the latest feature. The CDI would be in the $350-$400 range.
DISCLAIMER: The prices above are only "ball park numbers" and any final prices should be requested from your dealer. This just gives you an idea of what to expect for doing a conversion.