@DragonMail
That's akin to saying that F1 is similar to Top Fuel dragsters because they both involve cars, racing, tinkering with engines, and aiming to be the fastest. Sure, there's similarities, and they both grew out of man's need for speed, but they're different in principle.
So goes Initial D and WM in my opinion. They're both based on a real car culture that existed in Japan from the late 80s to 90s, so if you take a critical point of view, of course they'll seem similar.
To make them any more different would be misrepresenting the culture that they are portraying, and heck, I wouldn't read a manga about that.