The only down side well if you see it as down side, or extras coat on 24v is the plastic inlet manifold, they don't like turbo heat! And can in the worst case melt lol. More often they just distort. So metal short running intake, or some type of metal intake is needed in my opinion. But lots of people see this as an upgrade anyway so it not really a down side , just extras cost for initial set up But yeah they do make more power, mainly down to variable valve timing.