My 2005 xtr with -00 ECU had very strong surging problems and by strong I mean like riding a kangaroo, especially at 30 km/h. So what I did and what happened:

-Oil and filter service+NGK iridium spark plug+new cush drive rubbers+TPS replacment=70% better!!(I think new spark plug did most of the job, maybe it was broken?)

-DNA stage 1,2+removed snorkel+KEVs fuel mod(which arrived today, thanks KEV)+CO setting up by 10+tps set to 16+idle rpm set to 1500= additional 25% improvment.

Surging is now hardly noticable, actually i wouldn`t even notice it, if i wasnt paying atteniton and I can easily say the surging is actualy only 5% of the original surging maybe even less I`m very happy