I'm sorry, I meant it as more of a technical question. As in "Where do Touring Cars fit (in terms of mods and regs) as compared to DTM, IMSA, NASCAR, and the GT categories at LeMans?"
Well DTM were touring cars until they became “GTM” this year. They’re roughly equivalent to NASCAR in that they’re a derivative of stock road cars, just with a different slant. Like “stock cars”, touring cars can vary from rather pedestrian machines (production classes) to absolute monsters (DTM, Aussie Supercars).
Fundamentally, the different between a touring car and a grand touring (GT) car is that of body style. Hatchbacks and saloons are generally tourers, while coupes are generally grand tourers. There isn’t much to differentiate between GT4 classes and many touring car classes.