Some of this might be wrong

The performance numbers given for climb are at 100% power, and top speed is done with WEP engaged. Yup, some of it was wrong.
Bf109F-4 - DB601E engine, 1300hp.
Initial climbrate 3250fpm, 20k in 6.37 minutes.
Top speed ~385mph.
Guns: 2x7.9mm, 1x20mm cannon, optional 2x20mm under wings and 66 gallon DT or 500lb bomb.
Considered by many to be the "best" 109 variant ever, it's the most manoueverable of all the 109's in AH.
Bf109G-2; DB605A engine, 1475hp.
Initial climbrate 3500fpm, 20k in 6 minutes.
Top speed ~395mph.
Guns: Same as F-4.
The new DB605 engine was heavier and more powerful, so while the "Gustav" was better performing, it lost some of it's manoueverability due to the extra weight.
Bf109G-6; DB605AM engine, 1475hp. Currently a bug is giving the G-6 similar hp to the G-10.
Initial climbrate 4000fpm, 20k in 5.35 minutes.
Top speed, with WEP; ~405mph. Should be same as G-2 when corrected.
Guns: The bumps on the nose cover the breeches for the bigger 13mm MG131's, and the spinner cannon can be upgraded to the low velocity MK108 30mm cannon - a "one hit killer" against fighters.

Again, 2x20mm or 2x210mm mortar rockets can be slung under the wings, as well as the 66 gal. DT or 500lb bomb.
Bf109G-10; DB605D engine, ~1800hp with MW50 boosting.
Initial climbrate: 3500fpm, 20k in 6.25 minutes.
Top speed, with MW50; ~435mph.
Guns: Same as G-6.
The ultimate "Gustav" has the even more powerful DB605D engine, as well as a more streamlined nose cowling, allowing it to reach a much higher top speed.
[This message has been edited by juzz (edited 01-18-2000).]