I agree with that sentiment completely in regard to most planes for the MA. P47 for instance, I will almost always be taking eight guns and full load with 100% fuel to give me some times to use all that ammo. Only a mad man would take a c202 with the lighter weapons loadout....well, only a mad man flies that anyhow.
With the 190A5 in particular, but also with regard to wing pods on the 109s, I just cannot bring myself to put the extra weight on there and it does make 'a difference' in the same way having a full car load of people can:- It's subtle, only noticeable/dangerous when pushing the edge you are used to with an empty car.
Also, twin 20mm is enough to get more kills than my general life expectancy vs spitfires and la7s and gives me much more chance in those match ups when fighting from a disadvantage. Seeing as i generaly lack the patience to ensure I maintain the advantage this is a wiser option for me personaly.
As to my original question, the figures that are being thrown around here show scant evidence of what loadout, ammo weight, fuel weight, pilot weight, air pressure, weather, wind..... i could go on. I'm not doubting any claims just asking for a little more than some ballpark flight test figures in mile per hour.