Below is a very peculiar thing I found out today.
I have ordered spark plugs for my mothers Vitz RS (NCP91) on ebay.
These are genuine denso FK20HR11s. I got them for $30 a set of 4, so I grabbed 3 sets (shipping was something like $15). BTW these are sold here for $35 each (one plug)!
I was thinking of using rest of the sets in others xNZFE powered vehicles in the family.
While the FK20HR11 is correct plug for NCP91, it is long reach plug (26.5mm thread length) and will not fit earlier xNZFE heads (eg NCP65 or NCP13). The earlier heads use short reach plugs (19mm).
I still came ahead by buying from ebay 3 sets, vs 1 set in NZ, as I still have another NCP91 car that I haven't done the plugs yet in.
What is even more peculiar is that the head is the same part number between all 2NZFE and earlier 1NZFE, while the part number is different to 1NZFE found in later models.
So far I think best quick way to tell if it will have long reach is to check if it has drive-by-wire throttle and is 1NZFE (vs 2NZFE). The best way is to ask your Toyota parts person spark plug part number .
What strikes me really weird is I went through similar dilemma when buying plugs for my WRX STI, for some reason GRB STIs come with long reach while earlier modes come with short reach (both EJ207 motors).
I have no idea why would manufacturers purposely switch to long reach plugs... Perhaps better thermal management?
Just thought to share in case it could be useful to someone...