Both F2G-1 and F2G-2 used the same engine with identical power ratings. F2G-1 is clearly going to perform better primarily due to weight differences. This F2G-2 had incorporated carrier equipment, which likely added somewhere in the range of 100 and 300 kg, although my sources do not provide an exact comparison between the two variants.
I know that the F2G-1 and F2G-2 used different propellers. The F2G-1 had slightly longer propeller blades, while the F2G-2 used slightly shorter ones. In theory, the longer propeller on the F2G-1 could generate marginally more thrust. However, to my knowledge, different propellers on the P-47 series, for example, were not modeled to produce different amounts of thrust, so this distinction on the F2G series is pretty meaningless in-game.
TLDR: the F2G-2 would perform marginally worse than the F2G-1(maybe by 10 kph slower?), primarily due to the small increase in empty weight.