Interesting that somebody would steal tailgates. I wonder if you could slow down the thiefs by simply installing band/worm clamps around the hinges. Simple and cheap.
If you want to pay shipping you can find hardware at Mcmaster-Carr. Make sure you get the correct thread pitch. M12 can come in 1.25, 1.5, and 1.75.
McMaster.com.
I ran an oil separator on my 22RE for a long time. It made a difference keeping the throttle body and intake from getting gunked up. Buddies that run a separator on their 1FZ engines see the same result. I think it helps.
The purpose of those separators is to catch the oil that would normally pass from the PCV into the manifold, gumming it up. It has nothing to do with performance or MPG. Just keeping the intake guts cleaner.
Anybody that has taken the intake, or throttle body, off a 22RE, or 1FZ, understands the problem, and the fact that the catch can is the solution. I'm still trying to figure out a clean way to put one on my 3RZ.