Thanks for all the input here.
Seems ULTRA-POWER is rockauto.com's brand for selling surplus parts (according to a post on the toyota forum [1]). This means you might get a cheap Chinese one, or a brand new OEM one (or some top brand).
I see NDK.com ones on rockauto for ~$40, NDK at least have a website. Also STANDARD MOTOR PRODUCTS, which sell two, the more expensive of which is marked JECS which appears be a Japanese company [2] partly related to Hitachi and Bosch. Although seems that Japanese companies are manufacturing in China these days.
I might toss a coin, heads: I'll buy 4 ULTRA-POWER sensors and see what I get. Tales: I'll buy 2 NDK....
Cheers!
Ian.
[1]
https://www.toyotanation.com/forum/8...t-sketchy.html
[2]
https://en.wikipedia.org/wiki/JECS