I remember buying tubes of those two sealants some years ago, and one of them was modestly priced, but the other was around $60, IIRC, even back then.
The weird thing is, the FSM specifies that weird stuff that's red, and thread locker. I wonder if this is a misprint? Because when I took the timing cover off my engine, and the donor engine, and I know for a fact mine had never been removed before, the entire strip of sealant all the way around, including the water pump area was GREY. Other people, including ones on Subaru forums have ran into the same issue, and also wonder if it was a misprint of some sort.
I just use Toyota FIPG all around and no issues with it, I don't need to wait next day to add coolant and start the engine (was able to have it running after the assembly). The last Prius I worked on (head gasket) has that grey sealant on the water pump (outer side) which is totally unnecessary since it has a metal gasket. Extra time to clean it up. The o-rings are essential since they can leak and the gasket is just some sort of a backup. sometimes the FSM will go through all the unnecessary disassembly (there are always shortcuts) and they got lost into translation..
