i compared the charge from the 04 sti and 03 WRX... and they are exactly same build and size... only plug was different.. i felt more comfortable using the charge from the 03 which i know will charge upon impact...
Airbag is pretty direct yes.. but has to be very universal.. as a impact of 30mph.. or 80mph.... the airbag should do its job in both... i feel the charge if different.. will not change much..
i could be wrong... i hope i never find out..!