The base 3.0 is $50k. It will sell, but it probably won't be anywhere near as high as the I6 model if history repeats itself. Heck, even the I6s were the first ones to sell out in Japan.
Yes it has been talked about to death lol...
I believe the only differences with the JDM 4 vs 6 is smaller wheels and brakes, everything else is the same.
Edit: I recall BMW insider saying the 4 banger will also not have power seats.