Another go.....
If you have had the bike that short a time, you haven't
had the time to get a feel for what's 'normal'.
Start with the basics if you haven't already (surely you
have, right?). Any jetting should be done with a clean air filter, otherwise you are wasting your time.
Plug fouling in a kdx that has
not been rejetted is common.
Go to an '8' plug as jason said. An -evx is nice, but not a requirement. You can use a less expensive plug to set the bike up, then if you wish you can change to the rare-metal plug for reliability after the jetting is sorted out.
...and you didn't list your current jet-set. You can't get any reasonable advice on which direction to go if you don't say where you
are!
I read somewhere,
as much information and help as possible would be much appreciated.
;)