If the part is stuck due to threadlock on it, then acetone will help. Little bit at a time and let it stand for a few minutes to dissolve the threadlock. Use caution around the plastic parts since I'm not sure how it will affect the plastics on your car. I've used this technique many times on my VBC and AE chassis parts. I also soak screws, setscrews, nuts, and washers in acetone to remove threadlocker. Works great! Let us know how you make out.