Ok so the wifes car has a bit of an issue under WOT shifting

breakdown of the car

JZA80
3k stallie
GT35R 1.06 rear
FMIC
3 inch exhaust
bleed valve (17psi~)
fuel pressure reg with pressure bumped up
SAFC
stock injectors
Stock ecu

now i have been advised that the stallie is probably going to be too small for that turbo by MV... really needs to be a 3500... thats fine we can deal with that for now...

the shifting issue appears apparent at WOT and it will drop 2000rpm between gears... at part throttle it behaves correctly of about 700rpm on an upshift...

i suspect its the factory ecu retarding timing under the shift... which Mike also suggested as well as potentially be tune related...

I am just wondering if there is any other thing i have overlooked and if there is a way for me to get around this... (maybe make the car think it only ever reaches 99% throttle?)

not 100% sure how the whole auto and retardation on shifting works