After watching these four episodes (and err....future eps), if someone had thought that Wangan was street racing while Initial D....mountain racing, it is not just these two differences.
Spoiler:
Wangan focuses a lot on tuning and adjustments, where as Initial D is just......drifting...
And there does seem to be a plot...from all the racing, compared to ID4. which was just mainly racing with little to no plot.
And WM at least wreck their cars, not like the dentless Initial D
== way more realistic.
And funny thing is that I read on another forum that someone said WM isn't that hard to translate.