Those comments, as mentioned, are quite dated and I do not believe they are valid any longer, as much has changed since then.
At the time I bought my Steinbauer (which is still the setup I currently have) there were very few, if any reliable options for doing a remap. Now it is not a challenge to get a Canter remap; well, here in Australia.
I should also add that the FG84/FG140 does not have a DPF, so comparing problems with an Isuzu remap and DFP delete is not really comparing apples with apples.
As I eluded to initially, finding someone with experience with this remap process in the US is probably your greatest challenge.
In a worst case scenario, you could always go down the Steinbauer chip route, as I know the model I have on my FG84 is compatible with the FG140. You would probably have to source one from here, as the mapping was done by the Steinbauer importer/dealer in Queensland and I do not believe that model is available outside of Australia.
I have not seen him on this forum for a while now, but westyss has had one fitted to his truck for many years now, so you could PM him if you wanted real, first hand feedback.