Why does my car re-align after drift into the original direction?

Hi there.

I've been working on a "realistic" car sim since a couple of days but have been stuck since ages on this one specific problem. The problem is that, when I press space to drift, the car does drift but then it either

A. Drifts 180° and then comes to a stop or

B. Drifts a bit and then when I release the space bar it rotates back to its original direction it was facing before the drift, even though I am steering against it.

Here is my code: http://pastebin.com/aG9PfeB6

These are my settings:

Element 0 = Front wheels Element 1 = Back wheels