It's unpainted cast iron. Mine has a bit of rust but nothing like yours. I live in the dry west, and I suspect you live somewhere the humidity is much higher.
Take an acid brush and paint the surfaces with some light oil. It'll make you feel better, but without oil, that part will still last...
You need to change the design like Smartcap did and ensure the digital rearview mirror works through the cap.
And I don't think the door will open very high with that spoiler.
I think you can view transmission temp in the instrument cluster, eh?
The Care Care Nut on Youtube talked about these higher temps and he says it's because modern fluids handle them just fine.
Yowsers.
I had my ARB from the 3rd gen so other than plastic* it hasn't cost me anything. My Aux 1 switch turns it on.
*I don't recall how many prototype prints I did before I got it right, it may have been five.
It's a simple thing.
If you're doing 80 on the interstate and pull into a rest stop, let it idle for a minute. On the other hand, if it's -10Âş, let it warm for ten minutes.
That may have been me.
I developed a 3D-printed mount for it, and after 3700 miles, it's doing fine. You can find the file and instructions for it on Thingiverse.