You should not change ONLY the front bar, you need to change them both at the same time or they will badly imbalance the handling of the car.

Replacing the front bar is very simple and straight forward. Replacing the rear bar is much more of a challenge. You will need a good floor jack or two. You will remove the rear suspension mounts and lower the entire rear suspension enough to snake the old bar out and the new one in. Be very careful not to lower the suspension too much, or you will damage your brake lines.

I bought my Sportline bars at a Texas MB dealer. The sportline car was available in the US. Even so, a US dealer can get any part for a Euro car. I have driven a Euro car a half million miles and the dealer always came through with parts, even if they were Euro specific.

Good luck,