Luke,
You may not want to hear this, but the advice you are getting is spot on the money. A Spitfire (or any warbird) is going to be a handful to fly. You have to remember that fighters are designed to be fast and maneuverable, and that definitely translates to the RC plane. In addition to all of the characteristics listed by other above, a warbird does not land anything like a trainer will. With your trainer you can cut back the throttle and let your plane float in for a landing. As said above a warbird usually has a high wing loading, which means it will stall at slow speeds. To land a warbird you will need to come in with some power and you will have to fly the plane all the way into the landing.

My advice would be to put the Spitfire away and get more experience on other planes before you try to fly the Spit. I don't know if I would even recommend it as a third plane. If you try to fly the plane at your current skill level I can pretty much assure you that it will crash.

That's my 2¢ worth

Ken