Flex just shows poor build quality on the car and lowers output inside the vehicle. My caddy doesn't flex at all thankfully, the trunk is somewhat noisy and has been hard to stop but other than that, no real panel flex is present. At higher volumes my wipers will bounce, that's actually about it.
Umm yep new ones are trash as are the Mercedes. You replied like a true nut swinger that doesn't know what he is talking about. And FYI I have one of the last good models they made. An E38.