Lots of improvements were made just before the BoB like metal control surfaces, CS props, additional pilot armor, what made the biggest difference to high speed control was changing the aileron profile.
I think it was Winkle Brown who said the seating position and cramped cockpit of the 109 limited how much force could be placed on the stick, there wasn't enough elbow room.
Without the Spitfire and Hurricane there would have been no need for anything that came after because there wouldn't have been a base to launch them from.
Running 9psi boost instead of 16?. I don't believe for a moment that the Volkes filter is as bad as it is made out to be, if you look at other aircraft like Beaufighter it only lost around 3-4mph when tropicalised, likewise UK MkV Trops only lost around 7-8mph, for the RAAF MkV's to lose...
All I will say is the best threads we have ever had on this forum, well since I've been on here have been between members who have very different understanding or opinions on the thread subject. As each side tries to outdo the other, more facts come to the fore as members dig deeper into...
Any plane loaded up with fuel or ordinance is a handful on the ground as well as in the air at least until the fuel is burnt off and bombs dropped. There's plenty of room in the leading edge for 50G of fuel which is a much better option.
Having drop tanks is no harder than any other aircraft, all Spitfire's should have had at least the lower 33G rear tank fitted plus plumbing for DT's as standard, then fit the upper 33-42G as required depending on theater of operation.