cheap and best way doesnt go together, but if you need just a tad maybe u can torch them a little. that will give u a cheap drop, but not the best, and its free
i dont know if i'd do this to a porsche, but did it to my e30 bmw, and no difference in ride quality
but then again that car cost me as much as springs and install on porsche would be, thats y i didnt care