Keep a search active on eBay for "saab 900 tilt repair" and you may find one pop up cheaper. I found one for $165.
Randomly, I think I may have had a revelation on this note. I think it's possible the switch from NPT sensor to metric sensor may have been much earlier, and may actually have happened with the switch from the "long" B234 to the "short" B234. The earlier motor shared a head with the c900, which used the specific port on question for the temp sensor, which was 1/8 NPT. The coolant temp sensor (ECT) was always M12 anyway. I suspect when they went to the short block, they eliminated the need for the discrete gauge sensor, and switched to M12 threads to use the bog-standard Bosch M12 ECT sensor.After a bunch of reading, I think I determined that some time in 1997 there was a changeover, with earlier heads using a 1/8" NPT ECT sensor, and later heads using an M12x1.5 ECT sensor.