With no sulfur compounds turning into something akin to sulfuric acid to damage engine parts, this makes it possible to apply the very latest in engine technology to reduce fuel consumption of gasoline engines by as much as 15% and switch vehicles en masse to clean-burning diesel engines with 35-45% lower fuel consumption than gasoline engines! 
Here's what I mean:
In the case of gasoline engines, removal of sulfur compounds means we can apply direct fuel injection, stratified combustion and new ceramic-based catalytic converters that will cut fuel consumption 15-20% compared to today's gasoline engines and still meet the strict Super Ultra-Low Emissions Vehicle (SULEV) emission requirments.
In the case of diesel engines, removal of sulfur compounds means we can apply common-rail pressurized direct fuel injection and new catalytic converters that not only reduce exhaust emissions but also "burn off" diesel exhaust particulates at the same time. This means we can switch minivans, light trucks and SUV's to clean-burning turbodiesel power, which means 35-45% lower fuel consumption and still meet Ultra-Low Emissions Vehicle (ULEV) emission requirements.
In short, we don't need to completely redesign our vehicles, and we cut fuel consumption quite a bit.