The power band would be very narrow without any gain at the top. The VVT stuff is reliable is treated to decent oil and well time changes. The sump only holds about 1/2 a conventional engine so fresh stuff every now and again is worth it.
2012 onwards Aygos hit £0 tax band by being under 100g CO2/KM which was mostly done by switching to a thinner blend of oil, which owners swap out to avoid problems.
