Sorry for the confusion, I was only attempting to address the housing aspect of the question.
Yes, we do recommend welding in the frame. I usually recommend tacking it into place, removing the screws and welding in those holes, then finish welding the "cage" into the car, especially on a high horsepower car.
As for messing up the powder coat, unfortunately there is no way around that. if you are careful, you can limit the amount of refinishing necessary, but you will be doing some painting.
Tim

Bring this back up to the top to help me