The Spitfire is pretty much my plane of choice (mostly because it's the one I know how to fly effectively
) and I have had collisions in which my plane has come off the worse. I've also had the collisions where my plane manages to survive the blow.
If there is some kind of damage issue here, I don't think it's as bad as 'Spitfires are indestructable in collisions!'. It could be that the Spitfire just has a slightly higher airframe collision damage threshold or something currently that seems off. Could do with some looking at/adjusting if playtests proove that the Spits are abnormally more 'crash-proof'.
But, no, you can't use the current Spitfire as a battering ram with impunity. I certainly don't recommend it