Going back to the original post, maybe 600 mph could be a rough estimate, as I tested the Brewster offline in a dive at 564 mph and besides the stress sound indicators it flew flawlessly.
I viewed the trail it left as I pulled out of the dive and zoomed skyward and started to roll over, and I could see how these flight characteristics seem to be excessive. The keyword for me is seem. Being in a fight against one or two of them and the "seem" becomes larger. But there are a number of things that I can not comprehend in game. The number one being the seeming ability of a co alt spitfire to 180 flat turn and remain on the 6 o'clock of a plane flying faster than a spitfire's level flight speed.
I do however know about E state. It just "seems" that some planes excessively maintain their E state through multiple maneuvers.
Overstating the actual properties and sighting that flight characteristics are inaccurate does muddy the water. Therefore, if there is anything for HTC to test in the case of the Brewster, I would not focus on the dive speed, but possibly look at other effects such as blackout Gs, compression/ aileron response, etc.
Coalcat, I am sorry you went out on that limb, but there are many of us who are sitting on that same limb waiting to see if it can bare the weight. Unfortunately, there are those that are rooting for you to go farther out ......
Post what future films that you can, and let go of speed aspect of your observation..... I would also, pay attention to trails from planes in film that might explain a great deal.