Purely marketing and nothing to do with the actual chassis code. Its a BMW and it's code is J29. A90 is a gimmick, almost like the name Supra thats on the back of it.You should talk to Toyota's marketing department. My JDM Supra brochure that I picked up from the Toyota dealership has "A90 GR Supra debut" on the cover. -_-
Its not beating a dead horse, unlike what you propsed and delete everything "A90" its better to explain that its a marketing gimmick. Same as 100% natural, fat free, 25% less sugar etc. That tactic may work on the less informed consumer.Toyota themselves called it the A90 though. I'm not saying it's right just beating a dead horse at this point.