I'm not saying that it won't work without the SA663 option (although that may be the case
) but that all the OE kit instructions state that the kit applies to cars with SA661, SA662 and/or SA663 option Radio or Radio/CD units (along with SA650).
Bdc101 has the SA661 option so you would think it would work but again, I cannot find any info. on the Radio/Tape Player unit that is in there in place of the Radio/CD Player and this is the important bit, as it's this unit that needs to have both aux. inputs pins and software/firmware to allow the aux. input to function.
Frustrating, this lack of info.
Still looking....