Similar things have been done for decades. The Porsche 959 (1986-1989), Toyota Supra MKIV (1993.5-1998 USA), and FD RX-7 all had a sequential turbo setup, but t

Similar things have been done for decades. The Porsche 959 (1986-1989), Toyota Supra MKIV (1993.5-1998 USA), and FD RX-7 all had a sequential turbo setup, but they were all using two turbos of the same size. All The exhaust gas is diverted through a single turbo at low RPM to spool it quickly, then after a certain RPM is reached gas begins being diverted through both turbos equally. The problem is the control systems and extra plumbing get pretty complicated. The setup in the Supra is lovingly referred to as "the rat's nest"