Seems a daft idea to me, but its must be down to engine size as in a single turbo fitted to an engine that size must have turbo lag, and smaller twin turbos makes for complication with the exhaust plumbing etc hence the super charger which has been used on other VW models in the past, engine reliability wont be a problem, F1 cars used to be 1.5 litre remember and kicked out huge horse power, so a marginal output like this wont be a problem as long as the heat can be dispursed properly.