Did you get the answers you wanted above?
From your responses, I'm assuming they hit the mark, and what you're looking for is a Falcon Ute, as opposed to something like a Ranger??
Really depends on your budget, and your penchant for DIY repairs. No offence, but paying a mechanic $2k to tow and fit a 2nd hand box, does not sound very DIY?
I'm not having a go, its a serious point. Old cars are only cheap if you can do major work yourself.
Initially, I too would recommend the AU2. The Intech engines are very smooth (for a Falcon) and just about indestructible.
They fixed a few things on the series 2, like the brakes and some steeting components. If you're looking at a basic 6, then yes series 3 was a comsetic upgrade. (Much nicer interiors, but you can always buy seat covers.)
And yes, as others have said, the lack of an
ICC is s huge bonus. You can cheaply and easily fit a modern double-DIN head-unit, with a nice touch screen, reverse camera, DAB, satnav, android-connect, etc.
But yes (as others have said) these cars are getting long in the tooth. The issue with parts is that for some you may need to scour the depths of ebay and wreckers, which is fine for DIY, but many repairers will just say "nah, can't get the parts mate."
My 2nd recommendation would just be the basic "set your budget, and find the newest/lowest k B-Series you can afford."
Only thing I will add, if you should revert back to an auto, stay away from the ZF 6-speeds, as they are easy to break and costly to fix.
As long as you check the fluid level semi-regularly (annual service) the BTR 4 speeds are pretty tough.