Dose Pipe Sutututu

I think way too many people get caught up in the whole bigger TB for more power, but that's only if it becomes a restriction. In a FI environment, the TB size is not as sensitive, where as in a NA environment, you find with the throttle at 100% and if the plenum still registers a vacuum, then your TB is undersized and requires to be upgraded.

Is there a reason why you want close to 600kW in a R32 GTS-t? Have you thought about suspension work, subframe changes (from a newer car, offsetting it), diff choice, brakes, gearbox? There's a high chance you're running a RB20DET gearbox which will not like close to 600kW being sent through it. Also a 6262 won't get you close to 600kW.

I prefer to be in the car to hear/feel it, remote tuning isn't the same. Also when something goes wrong I can back off the throttle much quicker than trying to relay that to the dyno operator.

Could you ask them to give you the tune file? I know why some shops lock their tunes, so their customers don't fiddle with it and cause future issues/problems. Too bad you don't live in Sydney, could have hired a dyno and tuned the car together.

So one hose is out of production for RB25DET however it seems the RB26DETT one from a R33/R34 or Stagea "should" work. I am hoping it's 19mm like the RB25s lol. Anyhow, time to wait for over month parts from Japan (yeah this time I made sure to cover up my address lol).

Would only affect the low end, not the outright power produced. Also 180kW is about right for a stock turbo, you could push a bit more boost and make 190~200kW then hours later (maybe minutes) be ready to buy a new turbo lol.

74mm would be good, however you will find you will need to gently ramp in the pedal vs. throttle so it feels smooth and linear (not like those silly carb V8s where you touch the throttle 1mm and the car wants to fry tyres). This is how mine is dialled in with a 74mm DBW TB, I wanted 68mm but Plazmaman couldn't weld a 68mm flange onto the plenum. You said you want 373kW to 447kW, you don't need a 62mm turbo to do that, that turbo can spin over 500kW+

big throttle bodies don't magically make more power. You only need to go bigger if you have more boost pre throttle than post throttle when at WOT. 68 or 74mm DBW is more than sufficient for most people.

Fake GReddy = Freddy Don't waste your money, money better spent on good engine management, modern injectors, drive by wire (so you can delete all that cable throttle, idle control valve junk).

Most likely it's tuning related. That plenum is fine, moving to a Plazmaman you won't notice much of a difference. If you want supreme low down, better off with the stock intake manifold & plenum OR the Rajab top half. A Precision or Turbosmart 6262 is too big for what you want, and big boost with Tomei Valve springs also a fail. You can make 373kW on a stock motor with just head studs, sensible timing in the mid range and it will last for your intended purposes (won't last on the track for too long).

sounds like a good solid plan actually

maybe also pop the stock fan blade back on

What radiator is in the car? What thermostat and is the little bleed hole thing facing upwards? Is your clutch fan working?

I reckon there's a cheeky air pocket somewhere on the side facing the body

my bro-science approach tells me there's unequal force being applied from either side, hence the movement. If equal force is being applied, one would assume there would be 0 movement.