Me 109 K4 better then P51 D? I am doubt about that.
As you now, Me 109 had a engine with 2 stage compresor and P 51 D had a 4 stage compresor. Me 109 could flight at 10.000 meter altitude maxim, altough P51 D came over 11.500 meter - it has supercharger. That mean match engine power (speed cumulated)