So I have a little info on the "booster plug" for at least the 2022-2023 Svart/Vit 401's. The 2017-2019 booster plug from the manufacturer will not work on the 2022-23 models because the IAT sensor is a different style (uses Bosch TMAP sensor), different connector. Not sure about what the 2020 and 2021 models have.
By looking at their website it is possible that the 2013-2016 Duke 390 version would work as it appears to have the same connector, but no guarantees.
For me I just made my own by splicing into the IAT wire in the harness. I can see why they charge what the do because if you had to buy the connectors at $15 each and then the NTC thermistor at $10, plus your labor, plus make a profit.