Big Bore Kits

Ok if i understand it right, an XR400 cam will drop right in the EX without any head mods right? What are the power characteristic differences between the 416 and the 440? I know the 416 kit wll still use the stck sleeve. Besides the outside machine work, is it that hard to do these mods yourself with brains and a manual? Or is it worth paying dough to have it done? How much would it cost? I'm thinking somewhere around 10.5:1 compesion would be a good compromise, would you reccomed all these mods at once, just a stock high comp. piston, or which big bore? Thanks a lot!

Might as well do all that you can when the motor is open. If your fairly mechanicaly inclined you should be able to do the installation yourself with a good manual.