Hiro

15mm. They'll list the same part number because they have the same flange on the head and are "roughly" the same length, you would generally get an engine pipe/collector made up to suit. It's more of a concern if you buy a whole system from another car that has the different engine as it could lead pipes hitting the cross-member/sump etc

If it's 4-6km/h over at 100km/h then it is well within the ADRs (which allow up to 10% greater than actual speed) and entirely common for a new car these days (if anything your FG is an anomaly). It is standard practice for auto makers to have the speedo read slightly over anyway as it allows for manufacturing tolerances, differences in overall tyre diameters (and wear) and other assorted factors and still not read less than actual road speed (which would violate ADRs and open up a legal issue where owners could claim "my speedo said I was doing the speed limit" when fighting tickets in court)

Physically they will bolt up to the head, but the 7AFE has a taller block height than the 4AFE so they won't necessarily line up with the collector/cat.

Only time you turn overdrive off is if you're towing and you don't want the car to shift into 4th as it'll bog down. Most decent autos will also prevent O/D from engaging when the car is cold, but for the most part just leave it on and let the computer sort out the rest

$250 saved from roughly 40,000 vehicles (number of Hiluxes sold in 2014 in Australia) is $10 million dollars. Not exactly "cheap", and in no way limited to only Toyota.

Willing to separate the fog lights?

If you're considering coilovers, then look at MRP - Barry does some of the best 82/92/101 Corolla suspension gear out there for the price (and plenty of other good stuff too)

You'll need to talk to an approved club. Bear in mind that Victoria have recently overhauled their club/historic rego scheme to make it much stricter and less open to modified cars. https://www.vicroads.vic.gov.au/registration/limited-use-permits/club-permit-scheme

As Trent said I'm fairly sure both the 2AZFXE and 2ARFXE hybrid engines run timing chains (the non-hybrid versions of both engines definitely run chains) instead of timing belts. Timing chains, whilst replaceable, are usually designed to last the life of the vehicle and do not form part of a normal service schedule like timing belts do.

Repurpose a battery box perhaps?

Anything can fit with the aid of an angle-grinder and/or hammer

It does (of sorts - this picture is also of a 2GR-FSE but same arrangement)

I'm guessing he wants people to tell him how much it's worth...

You can't see the spark plugs in that picture because they are on the other side of the head. The oil cap (which you can see in the upper-right of the picture) is on the top of the rocker cover, the spark plugs will be behind there. Not the easiest things to get to but that's the problem with a mid-mounted van engine

If you can unbolt the mounts from the body it will make it easier, I know on the 20-series one of the mounts went through the floor/chassis into the boot area so wasn't removeable just from underneath. Best way to get the muffler hangers out of the rubber is good old lubricant and brute force - dishwashing detergent works reasonably well. Or just cut the rubber and buy new ones.

The bolts don't get removed, they're essentially studs (the weld is there to stop them from rotating), you only need a spanner on the nut on the other side of the flange. The new muffler should have bolts/studs already attached to the flange.

CIR is basically an ECU for all the body electrics in the car. Also called the Integration Relay, Body Control Module etc etc.

Australia did not adopt OBDII protocol until 2006 (everyone sees the US date of 1996 online and think that applies to the whole world - it doesn't), and whilst some overseas manufacturers did adopt OBDII worldwide in the early 2000s Toyota did not until 2006. Cars sold here made after 1996 may also have OBDII-style plugs installed to reduce costs but the wiring and/or software is not present for OBDII diagnostics tools to work. It may look like an OBDII connector but will not be a standard OBDII pinout (Toyota used a proprietary pinout and scan-tool during this period) - is there a diagram under the cap under the dash? If so then pin TE1 and E1 as you would have on the connector under the bonnet (from a quick scan online TE1 is missing from the diag port under the bonnet, right?)

Would be a much bigger problem if it included the petrol as that is also used in the Camry.

Punched the VIN into ToyoDIY and it came up as 07/1993.

Being a '98 model there's a decent chance it's not OBDII (even if it looks like it has an OBDII plug)...

Better to pull the EFI fuse, that way you don't lose radio presets etc...

Not a difficult job at all if you're even halfway decent with a set of spanners, no special tools required either (unclip wiring, undo two nuts/bolts, remove). Definitely would recommend getting the relevant Gregorys/Haynes manual for your model (should be an AE9x) just to make sure you don't miss anything, but since it's mounted on the front of the engine rather than the rear (which is where my 7AFE has it) everything is in plain sight and hard to miss.

Originally, Toyotas were built/assembled in Australia by a company called AMI (Australian Motor Industries), which over the years also assembled CKD kits from Standard, Triumph, Mercedes, Rambler, AMC and other along with Toyotas. Toyota Japan bought out a controlling interest in 1968 but didn't take full control until 1987, and only merged it with the rest of the Toyota operations in 1989, which is when the current Toyota Motor Corporation Australia (TMCA, "Toyota Australia") came into existence.

Considering the OP is not from Australia, who knows what version got delivered to their country?