Since these are inline engines the twin turbos are almost certainly a sequential arrangement with the upstream turbocharger optimized for lower-rpm and the downstream for the top end (both probably are active). There should be next to no turbo lag or peakiness.
With the gasoline small displacement turbocharged engines we are discussing here... the more noticeable phenomena has more to do with low torque at low rpms. The high horsepower and high torque numbers quoted are typically not reached on most until the RPMs are up around 6000 rpms regardless of the turbo configuration.
I once installed a two stroke engine that had no transmission, just a clutch on a mountain bike which had a very noticeable power band that caused it not to produce much power until you reached about 10 mph, then it would really start pulling. This is of course an exaggerated example but might give some the idea of the difference between a larger displacement engine with a supercharger which gives instant torque at low rpms and a small displacement engine with a turbocharger which has to reach higher rpms before it really starts pulling. Turbo chargers are best for mid to high end boosts regardless of the configuration. It is the nature of the beast.
“Superchargers provide optimal impact on larger engines with more cylinders and higher displacement. Without the turbo lag, you can access instant power across the entire powerband and achieve significantly more horsepower than with a turbocharger.”