Like I said in my post above, the car has TWO turbos! Read the second paragraph in the link below for additional insight, if needed. Sometimes the word twin turbo can mean two scrolls in one turbo, but not in the case of the 2015 M4 that I owned for three years. Below is the second paragraph in the link.
"The new-generation M car—which gets its own chassis code for the first time, F82—sheds its predecessor’s naturally aspirated 4.0-liter V-8 in favor of a quintessentially BMW straight-six. BMW has affixed the "TwinPower" moniker to the all-new, M-developed engine; the badging is applied to BMW’s gas and diesel turbocharged engines, and can refer to single, twin, or triple turbos, single or multiple dual-scroll turbos, or a turbo with variable inlet geometry. The M4 is fitted with a pair of Mitsubishi-sourced turbochargers."
https://www.caranddriver.com/news/20...-and-info-news