I finally had a chance to look at the Takom Panzer III Ausf. N with Winterketten. Unfortunately, I do not have a modern Dragon or Rye Field Panzer III/Sturmgeschutz III to compare against.
All parts trees look like they came out of every other Takom model in my possession.
The only other Panzer III in my possession is a built up but not painted Dragon Panzer III Ausf. M. If I recall correctly, this is based on a Gunze Sanyo model from the mid 1990s.
Comparing the Dragon and Takom hull pans, one can immediately see differences. With a bit of sheet plastic, the front, bottom, and rear surfaces of the Takom model could be made to match the Dragon model. When the Takom model is sitting on tracks, only a Panzer III expert will potentially spot an issue with the front and rear lower hull plates.
The more detectable problem is spacing of the torsion bars. To understand what is going on, I overlaid a side profile line drawing of a Takom Panzer III Ausf. M over a side profile line drawing of a Rye Field Sturmgeshutz III Ausf. G. Torsion bar positions on the Takom kit are spaced very slightly further apart, such that the rear most position is a millimeter or so too close to the rear idler wheel. I know that is a small amount, but once you know what to look for, there it is.
Shortening the rearmost torsion bar by a millimeter, then shortening every other torsion bar by a progressively smaller fraction of that, will hide the road wheel spacing issue. Surgery of this kind requires some serious model fu.
Based on what I have read, using the hull pan from any other not Takom model will also solve the problem.
Please note, this entire comparison hinges on an assumed fact: Dragon and Rye Field models are correct in all major dimensions. This fact assumes another fact: Panzer Tracts drawings are correct in all major dimensions. To prove the matter beyond a reasonable doubt, different teams would need to measure existing Panzer IIIs and Sturmgeschutz IIIs and publish their findings for comparison. Many people get upset when I bring this up, but we do not actually know anything with certainty until that happens. Repetition of experiments is a fundamental pillar of scientific inquiry and establishment of truth.
Please note, I do not own the Panzer Tracts volume on Panzer IIIs and thus cannot make any comparisons based on it. I know that is lame.
At this point, the writer usually offers some opinion on buying or not buying the model. You are all big boys and girls. Decide for yourselves! I am trying to be funny but seriously, do what is right for you.