Engine Performance

The G2 actually performs better than all 109's except the G10 model and has a nice gradual improvement in performance with altitude gains.  Sea-level speed is only average at 320mph (340mph with WEP) but improves rapidly up to about 7K where the cruise is 358mph (375mph with WEP).  That's an improvement of about 5.5mph in cruise for each 1K in altitude gain up to 7K or so.  Above 7K the improvements slow down but only a little bit, up to a high cruise of 385mph at 22K.  Top speed, with WEP, is about 405mph at 21K.  The WEP time is also very generous, over 9 minutes of solid use, so it makes extended WEP use generally more acceptable and you tend to use WEP more often.  Climb rates are excellent, over 4,400ft/minute at low levels and never drops below 3,500ft/min until you reach orbit.  Fuel duration is not good at only 25 minutes on full internal, one of the shortest in AH, but there is an option to extend that range with a drop tank (+18 minutes) which is almost mandatory.  Typically the drop tank can be used for the outbound climb and transit, dropped, and then internal fuel used for combat and return to base.  As such, taking less then 100% internal is not unusual, typically less than 75% isn't advisable though as it simply provides very small margins for combat.

Firepower

The firepower on the G2 is a little weak though well placed in the aircraft.  The spinner mounted 20mm MG151/20 cannons with 150 rounds is complemented by paired 7.9mm cowl guns (500 rounds/gun).  The placement of the guns in the cowl area makes convergence a non-issue.  Twin gondolas are an option but impact maneuverability and speed, to the tune of about 10mph.  The gondolas certainly aid when attacking bombers and give a more credible snapshot capability which makes them a tempting option.  Typically I find that someone with good shooting skills who is attacking fighters shouldn't need the gondolas though someone who is less confident tends to take them.  At least the G2 has some handling to spare so the gondolas aren't crippling like in the G6 or G10.  One of the key reasons people don't take the G2 though is that the G6, and later, have upgraded every aspect of the firepower to a more capable 13mm cowl guns and a much more impressive (though more difficult to use) 30mm spinner cannon option.  To be fair though, the cowl gun upgrade of the G6 and G10 is more important than the 30mm cannon option as most people can't aim just a large cannon against fighters anyway.

Maneuvering

The G2 gained ~450lb's of weight over the F4 series 109 but it doesn't seem to have impacted the handling as much as the shows in the later 109's (the G6 only gained 100lb's more).  You can feel the extra mass but for some reason it seems much more managable and well balanced than any other G series aircraft. That's why I like the 109G-2 , it can turn-fight or energy fight, depending on the situation and the external loadout you chose.  If you went light on fuel and didn't pack gondolas then you can turn-fight as long as you can keep the speeds at reasonable levels (not over 400, not under 250).  Lots of people might think you are just another G10 and not able to turn, thus you can quickly show them how wrong they are.  You can also energy fight though, the climb-rate, acceleration, and good zoom performance of the G2 makes it an excellent energy fighter.  Roll rate is good until you get to high (375mph+) or low speeds, where it becomes slow.  As in all 109's the G2 suffers serious control problems, especially in pitch, at very high speeds over 450mph.  If a 109 gets faster than about 450mph the only maneuver on the pilots mind will likely become compression recovery.

Flying the Bf109-G2

Offensively, anyone who knows 109's is going to recognize you immediately as a G2 because of the finnish markings and yellow nose.  Lots of people don't know what to expect of the G2 though so may discount you as just a G10 wannabe.  Try and BnZ them or slash attack them if possible and only resort to a turn-fight as a last resort.  Don't be afraid to use your turning abilities to give you a good shot though.  Use the vertical as much as possible,the G2 is a good climber at lower altitudes and accelerates great.  The WEP also lasts a long time so don't be afraid to use it as long as fuel allows.  Burn as much internal fuel as you can before you enter a fight, leave just enough for combat and the return trip home.   A drop tank can help keep your internal fuel load light.  Don't chase people on extended dives to high speeds as the 109 becomes uncontrollable and you will lose initiative trying to recover.  If you need to dive, cut power, use your rudder and roll with elevator to continuously bleed speed on the dive.  You need to watch your speedo closely though and level out at the first signs of over-speed (450mph).

Defensively, use your sprint speed, climb, and turning to extend whenever possible.  You should, if light, be able to turn with any plane faster than you and outrun any of the better turners.  Don't dive excessively as most other planes will be better divers with more controllability.  If you are diving make it a dive to extend towards friendlies so you can get help.  Sustained turning is good but if you can set up a good spiral climb you should be able to pull away from worse climbers, and a downward spiral can help you keep you airspeed within best range to maximize turn rate.  The 109 is not very tough so try and avoid any hits.  The radiator and fuel supply is quite vulnerable, both of which are a serious problem if punctured.

Fighting the Bf109-G2

All 109's have the same weakness to high speeds.  Over 450mph they all suffer terrible compression problems that can lead to almost total loss of control in a terminal dive.  The G2 with the higher cruise speeds and more power tends to get into trouble faster than some of the other 109's and picks up speed quickly in a dive.

Try and identify the 109G-2 early in a fight, which isn't usually too difficult.  Look for the wing markings (Finnish) and yellow nose as easy identifiers.  I find I can identify the 109G-2 at longer ranges than many planes as it appears to look slightly different as a dot (kind of like the P-51D).  In close though even a brief view of the wings and nose will allow you to notice a G-2.  If you can, see if he has gondolas also, as they can mean a lot to this aircraft.

Offensively, the G2 is a good turner, but only when light.   If he is obviously carrying gondolas he will be much less maneuverable and have less speed to use against you.  The gondolas tend to cost in upwards of 10mph under most conditions, speed which the G2 can't really afford to give away.  The 109's are all pretty small targets so can be tough to hit, but try and get in hits at whatever angles you can to damage items like the fuel, radiator or engine.  Views to the rear of the 109 are only fair so if you can sit low on his 6 he may not even see you.   Don't give the 109 snapshots on you if you don't know that he isn't packing gondolas, three cannons can make quick work of any fighter while 1 cannon is unlikely to cause immediate damage.  Keep your speed up if you are in a faster plane and extend whenever you can, be watch out since the 109 can accelerate and climb quickly and will likely build up energy faster than you can.  If you can fight at very high speeds, in excess of 400mph, then you can start to erode the performance of the 109.  If you get in trouble, dive away to 500mph or more and any 109 foolish enough to follow you will be in deep trouble.

Defensively, the G2 can be tough to shake since it can turn pretty well when light and has the acceleration and climb to stop any easy escapes if he can get speed parity.  There are some areas where the 109 is a little vulnerable though, and the G2 is no different.  109's don't have great views from the cockpit with lots of window frames obstructing almost every angle, so it can be possible to slip into blind spots or at least make tracking from the cockpit difficult.  The 109's all tend to pack too many, or too few guns too.  The standard spinner cannon is barely enough while loading the gondolas is almost too much.  If he isn't packing gondolas then the snapshot capabilities are fairly low, but with them he is heavy and has a lot more drag.  One great tactic, if you have altitude, is to dive away if you have even a fair diver.  The 109 is a crappy diver when speeds increase over 450mph.  It becomes more like a brick than an aircraft and can over-speed to the point where recovery is impossible.  Even experienced 109 pilots can find themselves plummeting helplessly while they try and use trim to regain control.