I did it and it's not terribly difficult. The Vee is restricted via the ECU (and under certain conditions by the secondary butterflies) in the lower gears to stop cack handed wheelies etc and by the secondary butterflies in fifth and sixth gear. Basicaly you open the throttle but nothing happens because the engine is not getting the full flow of air due to the butterflies closing. To access these you need to remove the tank and air filter. If you look down the two inlets you will see a round disc slotted through a bar & retained in place by two small screws, this is the secondary butterfly.
Carefully remove the screws, ideally with a magnetic screwdriver and the push down on the butterfly to turn it and grab the edge and remove. Repeat for the other one and replace the airbox and tank. You have now removed the 5th & 6th gear restriction and it will now fly !
A word of caution, Suzuki did this because they had some worries about stability. Make sure you bike is tip top before exploring the upper reaches of the tacho in 6th !!! Mine had the Hagon springs with the forks dropped through the yokes about 15mm and +25mm jack up dogbones at the rear and it was quite stable, only getting a little bit 'floaty'. All done on private roads of course...