That's all very very interesting that lot there Chris

As you say it's nothing that you've not spent time investigating and talking to many others about in the the past, way back when............I know because I've spent the last couple of weeks burning the midnight oil looking through anything 90/95 series suspension related on the net

Those photos are now missing from off of your original post on this subject Chris, back on TLCOC and as said peeps having already been running all of these mods for many years already including the use of 80 series front springs in the rear of a Collie/Prado. This is more a refresher course if you like
So, when I left on the school run this morning there she sat in the cold light of day and I would think no longer able to fit under the height restriction at the local dump!!! She looked way too jacked up to be useful and I spent the morning pondering if I'd got it wrong before I had a chance to get back home to have a play with her.
Here's some numbers;
Now here's the thing, following my many hours spent trawling the 'Net for suspension lift information there seemed to be little use of a standard point of reference in terms of what everyone is measuring so I measured the lot (top of rim, center of rim, bottom of rim, ground) all from the underside of my plastic arch body molding, through the center of each wheel down to the ground.
Like this;
Now for me this works and I can see any difference in height due to different springs or loads as I'm always measuring from the same point on my own truck in the same place on my own cobbled block paving (I'll come back to this in a mo'). Now if you have 255 tyres like me then the tip of your tape will touch the plastic molding in roughly the same place, but if you have this size tyre with wheel spacers or even a different sized tyre say a 285 or even a 305 then your tape tip will touch the molding further out to the outside edge and if measuring from there on my truck I could add up to 1.5cm to each of my measurements as the molding is not parallel to the ground. I guess what I'm saying is that everyone's measurements are going to have differences dependent upon there own circumstances and that you should bear this in mind throughout.
Just quickly, how do I know I'm always pretty much parked in the same place for any measuring. Well I've had a cross marked on my paving for some time now and so long as I park my truck parallel to the paving with the rear of my tow bar central and in line with the cross and can make a pretty good comparison measurement between test drives
So, my findings;
I'm only going to use the averaged measurements for each side of the truck from the plastic molding to the top of my rim to keep things less cluttered.
These were the measurements I took of my SWB manual 3.0TD 90 series Colorado/Prado with an Ironman 'B' spec suspension lift front and rear. Nothing in the boot (no load), no fuel (orange fuel light is on) and with the back seats fitted (being a shorty it only has one row of back seats and these are the ones I'm speaking of).
FRONT 320mm
REAR 335mm
OK, so now the same measurement with everything exactly the same as above except the rear Ironman springs have now been replaced with new KYB standard 80 series front springs (part number RF2574).
FRONT 315mm
REAR 405mm
I'll let you do the maffs
One last point to make is that when I bought my IM suspension kit it was sold as a 35mm lift. It would appear that it is now sold as a 45mm lift. So if we average these two figures and say that I had an 40mm lift from my IM suspension kit and discounting any sag that there may have been from two years of good use then one could say that I've gained a 110mm lift over standard by fitting the 80 series standard front springs.