I've built one of these G-6s (well, mostly) and there's a couple of things I'd add.
There are mistakes in the instructions relating to the nominally early and late versions. Keep your wits and references about you when checking which parts are for your aircraft of choice. You can build a G-14 from this kit with no additional parts by the way.
There's nothing wrong with the wing mounted wheel bumps on this kit. This aftermarket is produced for the subsequent G-10 Erla as it only supplies the large wheel bumps and both schemes I believe require the small ones.
The MG131 beulen are a weak spot. They are too something (I cannot recall if they're too small, big, fat or thin ). I used spare Hasegawa G-6 ones which look better. I also used Hasegawa prop blades as they looked better I suppose a Henri Dahne would be the ultimate upgrade here (lovely work).
The 'pit is pretty good in my opinion. A little bit of extra detail scratched in would help and as Thierry says, get some replacement seatbelts (Radu's are still the best).
Get rid of the horrible, totally un-prototypical 'hinges' that attach the canopy. The canopy was attached by pins at either end which were invisible. Watch out for the fit of the rear bulkhead behind the pilot's head. It should sit flush with the fuselage sides (if you see what I mean), there's no ridge around that part. Here's an image that shows:
U/C is a bit of a tricksy assembly and may be quite weak, you have brass so no worries there.
Elevators and ailerons have oversized 'disks' on them that represent something barely visible on the real machine. Quite tricky to remove without damaging adjacent details. A2Zee did these as part of a set, not sure if that is still produced under the new management..?
Raised area at wing to tip join is a bit of a gross exaggeration of the tape used to seal the joint (often seen as white/pale lines on this area). Sand right down, probably best represented with decal or paint..though I'm sure many aircraft didn't even display this feature as tape was painted over by camo?
Hope that helps. Mike and I did a review/guidance notes on this kit a few years ago. Not quite sure where it is and know that most/all images were bludgeoned by good old PB, bless them...