Dudes, it all depends on the eyepoint.
In my g6 i outturn/scissor every p38 and im able to kill them unless they have serious advantage at the beginning.
I bet the better p38 pilots out there have the same experience about the 109s, of course with the opposite result.
I THINK the 109F completely outclasses the p38G, and the G-6 is in par with the J/L, being a lil bit better in close combat while the 38 is a better energy/BnZ-fighter. Its my opinion, based on interaction with some better P38 pilots.
<S>
Edit: the g6 is almost in par with Las, Jaks, Ki84s, ki-61s, p40s, F6Fs etc from the same category, depending mostly on the pilot who will be the winner. The p38 CAN do the same, and with a decent pilot who has good SA in the 1v1 and able to realize when he will be unstoppable in the rope, its a real decent turnfighter.