(E4)-------F4-------G2/G6-------G14--------K4
<TnB..........................
.......................BnZ>
The 109s models in AH show the same kind if gradual evolution as the various spit models: Each step up on the ladder they sacrifice some flat turning ability for additional power (translating into more speed and higher climbrate).

The 109E is a difficult beast to fly and very different from it's later brothers. Poor guns, little ammo, not aprticular well climbing and most important: A horrible rate of roll.
The F-4 is a true furballer, that will surprise many a lazy Spit 16 pilot in a flat turning contest.
The G-6 is basically a heavier G-2 with bigger firepower. The G-2 turns & climbs slightly better and is faster, the G-6 has 13mm MG's instead of the 7.92 ones.
The G14 is perhaps the most "flexible" of all 109's with it many armament options (20 or 30mm hubcannon, gondolas, bomb).
You take the K-4 if speed is absolutely crucial, it's actually fastest prop plane between ~8k up to ~24k where the 47M takes over.
From G-2 on, the main strength of all 109's is the vertical fight - even the "older" ones can outclimb most opposing fighters in late war MA.