[vanir]

See that G-6 had noticable worse performance then G-2 both in speed and climb due to its gross weight and worse aerodynamical shape. We dont know how much worse it was but German pilots reports that G-6 has noticable worse in handling and turns and describe it as a "heavy"

This is only an opinion I have.

I believe if you source these pilot reports you'll find they're for the G-6 fitted out as an interceptor, with MG-151 gondolas and a drop tank. I've got one such detailed report handy, made by a new recruit in Reich Defence Jan 44 describing the "heavy handling of our G-6s" because they were fitted with too many external stores for an already high wing loading to begin with, an airframe he says was too light, and a motor which was too powerful for it. He said many recruits killed themselves on the runway simply by opening the throttle too early, and pancaked onto the roof crushing the cockpit. It was apparently a very common type of accident at the time among recruits, no wonder the type got a bad reputation!

Many experienced pilots seemed to quite like the G-6 (flying clean) by comparison. A large number of JG54 pilots converted back from the 190A to the G-6 during 1943 and didn't return to the FW until 1944. The reasons for this is however unclear (I guess it could've been production deliveries but generally field commanders and their pilots seemed to equip what they wanted). Many Jagdgeschwader exclusively flew the 109 and made this decision right when the G-6 was current, which would seem a little odd for any disadvantaged handling capabilities. Several aces swore by the G-6 and didn't differentiate between this and any other 109 model.

If you recall there was a time when pilots were reluctant to give up their Emils for the 109F. This was similarly most likely due to a spate of fatal and near fatal accidents early in F production for which the F-1 was grounded until the rear fuselage structure was improved. Then just when they got the F right in the F-4 which was a beautiful aircraft, the G came out and started killing pilots (this was due to flaming issues with the 605A engine at high boost). Then performance was capped until October 43. And in early 44 it started killing the poorly trained recruits that the Luftwaffe was forced to send up.

I agree with pilot commentary that it was too heavy for external stores, and had always been designed more like a racing plane that a heavy fighter, so needed to be kept as clean and light as reasonably possible.
Plus the poor low speed handling characteristics of any 109 couldn't have been helped with the extra weight of even a clean G-6 (or G-5 or K-4 for that matter, being even heavier). Marsielle used to say his secret was learning expertise in the low speed handling of the 109 (the first rule of successful aces is surviving take off and landing).

So I do not think the G-6 should be very heavily penalised for handling over the G-2, flying clean.