Well here is a neat link on the forces at work on a banked curve:http://hyperphysics.phy-astr.gsu.edu/hbase/mechanics/carbank.html
But it does include friction but it will at least give you a really good idea as to what exactly is at play here.
Hope it helps.
I guess you could say that but the path and final velocity would be different for each angle. The problems I have always dealt with specify how to pick the angle, but if we are neglecting air drag and the curvature of the earth then 45 degrees would be probably be the best angle to chose.
I am by far not qualified to really answer this but just from thinking about it. Wouldnt the air deformed by the front of the car move downward to fill the area of lower pressure between the roof and trunk on the rear of the car. Thus creating a downward force on the car which I assume would be...