This is the only thread I found specifically on the issue, it's mentioned here and there all across the forum though.
Looks like the toyota red is less acidic and has less silicates, but its not an actual issue on our iron block 2JZ's, jury is still out on the aluminum 1UZFE though as it may be that toyota red is the most beneficial for the 1uzfe. However, that being said I'd still stick with Toyota red coolant diluted with distilled water in my 2j than green coolant, which I found is also ethylene glycol based. But it may not be as dire of an issue as I made it out to be.
To be clear.
No color coolant will rot the radiator lines.
Orange dexcool will eat away at the gaskets and metal and should be avoided in all vehicles.
Ethylene glycol green and toyota red are fine in the 2jz.
Ethylene Glycol green may not be the best in the 1uzfe, but I'm still not sure.
Toyota red is less acidic and doesn't contain silicates.
Toyota red will gunk up around leaks and can slow the leak.
Toyota red and green should not be mixed because they'll turn into something resembling jello.
Toyota red is also a bit more expensive than Ethylene Glycol green.
Sorry for causing confusion with my first post, I was trying to speak on something I only half remembered from over a year ago.