There Will Always Be a Lawsuit
Lawsuits are the American way of life. You just know that there will be one, if not twenty, lawsuits in the wake of the death of Paul Walker. I'm not sure how far you're going to get by suing the maker of a car like the Porsche. Lawsuits are vastly different in Germany. Basically, the German legal mind would look at what happened and say, "if the car was mechanically sound, you can't sue because you did it to yourself."
I don't know if that will work but this was a car that had six different owners. Are they all liable for any modifications to the car?