zlehmann, if you're lucky, you'll meet a smelly Spitfire pilot like myself. If you're unlucky, you'll meet one of those rare pilots dedicated to flying the spitfire so well, they can knock down some of the most experienced players.
Im simply a mechanic-in-training so i'll try to give as many pointers as i can. the spitfire did save my uncle's country after all, along with the hurricane.
The spitfires are very light aircraft. A spitfire IX weights about 5,749 lbs empty. An La-7 weighs about 5,850 lbs. empty give or take. Given the better acceleration of the La-7 in combination with more weight, it will zoom climb a little better, meaning that if a spitty and an La-7 both dove to a very high speed and pulled up at the same time, the La-7 would climb ever so slightly higher than the spitfire IX. You'll also dive faster. Just don't run in a duel past 2.5 K, as that's just not dueling anymore, it's running. Plus Spitfires have the wing washout affect or 'wing twist' which disables good response of ailerons in speeds of excess of 410 mph (while the fabric ailerons of a spitfire Ia will lock up at 350 mph). Forcing them into high speed turn fights may work as your more heavily wingloaded plane will turn tighter at those speeds.
Another disadvantage is that spitfires have only 2 flap settings: full deflection or none at all. Sometimes, they'll use this for overshoots. Other times, they'll be just try to turn with flaps on. The la-7 has multi-stage flaps meaning that it can have a tighter turning radius without too much drag. Spitfire XVI's are usually noobish and won't turn with you. Others have past that 'danger zone' (which is pretty much the point at which many planes' learning curves seem to intersect; i.e. a green F4U pilot will lose against a green Spit16 pilot, while a more experienced F4U pilot will maul a more experienced Spit16 pilot, and then theres that place where the plane just wont cut it anymore - where the pilot's skill is THE biggest advantage regardless of which plane they're flying - F4U or Spitfire, La-7 or P-51). When theyve gotten that good, you better watch out.