Guy from Alpine Motorsports did mine however I would not recommend them.. guy was a total d*ck on top of not coding the red seatbelt light on my dash. Not sure how others are retaining factory seatbelt sensor since it's permanently attached to the factory seats.
i just went to the local (Belgium-Europe ) bimmer coding company. At first it didnt work but with some specific Supra updates he was able to code the seats.
it’s mainly the seating position that needs to be coded out i think.
i removed the seatbelt clip (incl wiring) from the oem seat and mounted it on the seatframe of the bucketseat.