Hoped we'd get a few more guesses first!
But Bingo!
Well the 'out of balance' as being a stand-alone issue, is really a bit of a red-herring and a
consequence of the primary issue, not the prime mover:
The high MAP sensor pressure proves the issue which then led to inspection and confirmation of Vac leak on the hoses to the TB's due to ruptured hose.
The initial problem description - hesitation/surging is fundamentally symptomatic of lean condition.
A lean condition can be caused by (obviously) too much air or not enough gas;
The 'not enough gas' (fuel pump or injector issue) can be reasonably dismissed as not the problem, as once past 3K opened up perfectly.
i.e. not a fuel starvation issue.
Most non-std maps would be more likely to add fuel anyway, so 'bad/incorrect map was unlikely (while not impossible) conclusion.
So that leaves 'too much air' which is invariably a leak - with the most likely cause being through the TB vac hoses (especially on a 10+ yr old bike)
I had already suspected the leak and the data from the TuneECU MAP sensor confirmed it, then it was up to the guys on the ground to locate it from visual.
After leak was repaired, it was then RICH!
That is not unusual either:
While the ECU was trying to compensate for the lean condition as sensed by the O2 sensors, it created adaptive trims to try to offset that
i.e. it was adding fuel to the base map config and creating a long term fuel trim that was weighted heavily rich by 'normal stds'
Then when the leak is fixed, that trim is still applied.
The simple fix there is '12 minute tune' - but the guys flashed in a fresh map and reset adaptions which accomplished same to remove that previously accumulated trim.