Personally i wouldnt go any lower than 30mm,you can go really low if you want for shows and that but for normal use be it on track or road then around 20-30mm.I wouldnt assume that really lowering the car will make it handle better,you might get a surprise and actually make it handle worse.(it might look better though)Also the splitter is not the lowest point of the car,the sump cover is, and i would be worried about speed bumps and practicality if it was really low.