Hi Shift, have you done any comparitive flight testing, especially flat turning with the Spit14 versus the 16 say? If you have and filmed it I'd love to see the results. While I agree on paper the 14 looks like a boss in practice for me at least just doesn't seem to translate. I have trouble turning it below corner speed, the pitch seems closely coupled to the yaw contibuting to the nose bounce so your boresight traces an elipse. Then there's the nasty uncommunicative nose-high-when-slow departure which leads to a very nast spin. Discounts the kind of tailstanding reversal antics the K-4 boys get away with, you just can't risk it in combat in the 14.
In testing I've even entered this departure engine off, so I've discounted the torque. My feeling (subjective feeling) is that the CofG is modelled incorrectly - too far aft. Not even the Spit historians I've asked know of any evidence of these handling issues in real life.
Also there's the WEP. Five minutes which is often one decent fight, after that rather feels like an overly-heavy Spit8 with that hobgoblin from the Twilight Zone fiddling with your surfaces. Very bad news because by then three LA7s have usually shown up 
Yeah Ive compared the 14 and the 16. The 16 has a sixteen second turn, the 14 is closer to 16.5. This is for flat sea level turns with max wep. I cant say I have run into any of those issues when I fly the 14. To me it feels exactly like a faster 16 with a worse roll rate. In my experience alot of people who prefer the 16 like it due to its roll rate, since that makes it a much easier plane to furball in. I am usually in the Mustang in the MA, but I switch to the 14 which I'm in am impatient mood. I find that you can stay right with a 109 in any kind of fight with any contemporary spit. In fact I generally see the 109 as being easy meat when flying a spit. Especially at altitude. I dont have any footage of me in a Spit 14 unfortunately.
As for La's, I tend to stay on the periphery of the fight until the tactical situation permits otherwise. Any engagement bigger than 4 v 4 is more or less a crap shoot, unless you have a big altitude disparity you can exploit. Aside from that, once you get a big dogfight going it is usually decided solely by the accidental positioning of x fighter behing y fighter, and the incidental timing of reinforcements. This is one of the reasons I like the 14. If you keep fast, you can skirt the battle space and engage enemy fighters when the timing is right. In a 16 you can much more easily get caught in a no-win situation.