How to verify OEM spark plug compatibility Prius Gen3

Yes, that's the denso one. Which is good also.
I'll have to find the one from illinois.... He shows the parts, like the oil filter.
The cheap chinese copy one is soft and flexable. The Toyota one is a lot firmer, and solid.

 

You are just kidding, right? Have you never had to fight out a small seized bolt????
I know bosch coats the threads on there plugs... Not sure about anyone else.

 

Found it!
Counterfeit Toyota Parts Video:

 

Well, the spark plug is supposed to be tightened only to 15 ft lb and the spark plug hex is a 14 mm size, so you are able to exert pretty good torque when removing it. With my limited experience removing the 2015's spark plugs once, it didn't seem that removal would generally be a big issue with the rubber seal on the spark coil keeping the spark plug tube clean and free of corrosion.

Compare to Classic and 2G where the spark plug is a little larger in shell size, and I recall occasions where I was wondering if a plug was binding while trying to remove it.

 

If it feel tight, I unscrew it like you SHOULD use a tap. Turn a 1/2 turn, then turn back 1/4 turn.
Usually the last few threads have carbon build up, that's why it's tight.