The P-47s in question carry the 108/110 drop tank under the belly, while the Mustang X has the original 180 gals of fuel internally + two British 54 US gal (45 imp gal; the type used sometimes on Hurricanes) tanks under the wings. The two Allied fighters can reach to about Hamburg or Frankfurt, and there are hundreds of these fighters in service; there is a supply of the drop tanks to support this. They give the LW defenders a proper mauling during already before the summer is over, and the things can only get worse for the LW, as well as the ones on the receiving end of the Allied bombing. Germans don't know when the long-range Spitfires will be also included - IOW, expect the worst case scenario there, too.
This is where the German answer starts, 1st tossing the ideas around, and then making the actual hardware (aircraft & the supporting bits & pieces; the Flak development can get another thread).
Note that this thread is not about what RAF aircraft gets the cameras, nor what gets sent to Russia.