Well, the original quote was in an interview, rather than a press-release, so he could just have misspoke. Time will tell.
“The chassis for the M8 road version is built in the same line as the GTE cars, and the engine location and transaxle concept are exactly the same in both cars,” says Marquardt.
That is what I was remember as well. Thanks for quoting his statement

although it's a personal statement rather than an official press release, it is coming from a director in the company itself. I can understand, however, that Marquardt's position is related to manage BMW's motorsport program, and he isn't related to the development of the road cars. Maybe I should take his quote with a grain of salt, but for sure, time will tell...
That would be weird, wouldn't it? Marquardt is fluent in english and has a solid technical knowledge... can't really think of a "misspoke"? Or the journalist was incorrectly noting down?
There is a possibility that it's a misconception or a misunderstanding, either from Maquardt or from the interviewer. From an economy or a business case point of view, it doesn't make sense to do significant modification to the chassis, unless the CLAR platform has the flexibility to allow such modifications to the whole package without increasing the development costs too much. I don't have enough knowledge or information to back this claim, so it's just an opinion.
Although it's just some wishful thinking, I hope that this turns out to be true, and the same concept will be unique to M cars and can be transitioned to other models in the future, at least for the next M4 and M2.
Anyway, regarding the original topic of this thread...
Personally, I don't care that much about large coupes, as I'm not a customer, and I like smaller cars more. BMW is almost my favourite car brand, but if I want to own a modern Bimmer coupe I would choose the 4 series even if it's less luxurious, flashy and refined.
I haven't seen the new 8 series in real life yet, so all I can care about is if I'll like it when I'll see it. I can assume that the wide-and-low stance along with the lines will grab my attention, but this usually happens with other cars as well, especially the large cars with the same stance (low and wide), but will I like the car after seeing it over and over? Compared to the outgoing 6 series coupe, I prefer and still like the looks of the 4 series. So, I can't answer the question of this thread for myself until I see the 8 series for some time.
From a technical point of view which is another special perspective, I can understand that some people are looking for something special, unique, and not shared with the rest of the lineup, whether it's a dedicated chassis or an exclusive drivetrain. Then again, I'm not a customer, so it's doesn't make much of a difference if I care or not.
What I really care about is how the racing versions perform in GT championships

In the end, customers who like a certain product will find the means to justify their choice, while people who don't like that product will find the means to disregard it.