Uhm, phase amps is what going from controller to motor, so nothing a battery would see.
Stock controller puts out 450 phaseA, at least the ones from 2018.
You will not see a higher phase amps with the NUC.
Stock cells can handle 110A max and you will already see a tremendous voltage drop at this power. and thats what you really can get with this controller on the stock pack. Bonus is that you will kill your cells faster. Not really worth it IMO if you dont have a better battery.
At 90A, which is what the stock controller suck out of the battery you already see more than 5V drop so at fully charged battery you have like a maximum(but probabaly even less) 62,2V * 90A = 5598W
at 110A you prolly have at least 8V drop so 59,2V * 110A = 6512W
The stock setup at 90A is pretty much ideal if you like to have a long cell life, at these amps you have 8,2A draw on each cell. Ideal would be 7A or less.
Then of course, you can, for some reason, like many on FB like to do, a bypass and definitely kill the cells without getting a noticable performance increase.
I have these KITs for sale at 4000USD but every one is already taken

Original Case from Sur-ron for a perfect fit without mods.
72V32Ah 2304Wh (more than this simply does not fit) 20s8p Samsung 40T cells can do up to 280A.
300Amp BMS with BT
Original charger, but for 72V battery with 10A
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