I think this is how I would do it.
1 and 2 are profiles, 3 and 4 are rails.
Then I project a curve on that surface and trim it.
That is if you want to have a patch right there. But I would actually have a bigger patch going all the way to the end of the car and then I would trim the wheel out of only one surface (isntead of the many that u'll have doing it that way).
There can not be Good without Evil, so then it must be good to be Evil sometimes.