Questions on individual acceptance

Hello! First of all: if I’m wrong here, please move. Thought this would fit in best. Unfortunately, I didn’t find an answer to my question anywhere in the net. It’s about the following: I play with the idea of ordering a coilover suspension from the USA for my BMW. Not to save money (since everything is cheaper there). The problem is that the suspension is not available here in Germany. Also in the USA the suspension is only available for special dealers, since it is a kind of promotion action. I would have the opportunity to get to such a chassis over a few corners. It is also not a cheap part. Supposedly it should act at the level of the KW Clubsport. Who knows, this should be tested out ! Now to my actual question: wanted to pass the whole possibly by individual acceptance. I already wrote to the manufacturer about an expert report, but still wait for answer. So it is the case that with the Just the name that it is for my vehicle. Do I get registered with such a thing? I read that the TÜV no longer makes an individual acceptance without expert advice from 2007 onwards. People who can build a car completely themselves can do this without breaking the law. Doesn’t it suit the examiner if he can convince himself of the workmanship and quality of the chassis? That would be the original sense of an individual acceptance, right? divide that fall outside the rule. I already thank you once in front of out! Greetings Dominik