If your OEM visor clips haven't failed they will soon - its almost guaranteed. But instead of going back to Porsche for expensive parts, try these replacement clips (above). They're almost identical in shape, work perfectly and fit like a glove. They utilize a steel spring clip and a small bezel. They will grip your visor with just the right feel and won't break, or allow the visor to droop. Replacement takes only a few minutes and can be done by anyone with a simple Philips screwdriver.  These clips are available in black only.

Side Note: The broken clip seen above is 13 months old. It was replaced in July of 05 and failed after only one summer of St Louis heat.