[ukrkoz]

Interesting.
I could swear, it always was iridium tipped.
Oh well, it is what it is.
My NX200t required plugs change at 35 000 miles. I see new trend ...
Either way, OP, you'll have to hassle with rear plugs. You either pay dealer over $500 to do the job or find a creative mechanic that will figure how to do it without cowl or plenum removal. I had a guy who did it in an hour for $200 plus my plugs.

 

[ukrkoz]

And BTW.
No one says you CAN"T put iridiums in, right? And be happy for long time.
Otherwise:

Search results for query: spark plugs

www.toyotanation.com

 

[ukrkoz]

Before making any decisions, call dealer with manual in hand. Or, better off, drive there, to look them into eyes.
Stand in front of service person and ask them to repeat "120 000 miles" mantra. Then, read part where it says "required at 60K miles". If they still insist on 120K miles, ask simple question:
How is it influencing my vehicle warranty?
Though, power train will be out of it anyway, by 60 k miles, aye, mates?

 

[ukrkoz]

Please, call dealer and ask. Or, email Toyota.

 

[ukrkoz]

Pluigs are good for 110 000 miles.