I would like to point out that this engine is not a sequential twin turbo setup like the article states, but rather a parallel twin turbo setup. Essentially, 2 smaller turbos are used, each being fed by 3 cylinders. This helps to reduce lag.
The comparison to the MKIV Supra is interesting, but stock for stock, the BMW will have way more torque at lower RPMs, even though the peak numbers are similar.