^ you are absolutely right.
JDM = Japan Domestic Market
Term is loosely used for anything made in Japan, these days. Used to be used only for something like OEM parts that are available exclusively on Japan cars only.
As for the specs on the TE37 Gun Metal, it is 19 - 9.5 et22 and 19 - 10.5 et20.
we have done about 6 cars with this set up so far and the best fit seems to be with the 265/35-19 and 295/30-19 tires. They seem to be the closest to the stock radials in terms of OD and front/rear bias.
love the pics....