Assuming the 16v injectors have a higher flow rate (they probably do), then in open loop mode (wide open throttle) it will be injecting more fuel. If this is too much more, the spark will drown and the engine will miss fire. But maybe it's only slightly more and still works? This will not really provide any more power and is just as likely to provide less power. For normal running, the lambda sensor should allow correction of the mixture so the ecu will reduce the injector duration to compensate for the higher flow rate.
Most likely any improvement you see is caused by replacing a faulty injector with a good one.