What should I look for in a used Honda S2000 sports?
It's a Honda which means it'll prove more reliable than most others. That said, repairs won't come cheap.
If you're looking at an S2000, first check it has had a service at least once a year and that high-quality semi- or fully synthetic oil is used. Be prepared also to check levels weekly and top up frequently because oil consumption of up to a litre per 1000 miles is normal.
Next, check that the hood raises and lowers as it should and that its fabric is free of rips or scuffs - a replacement will cost over a grand. Cars made before 2002 have plastic rear windows (later ones have glass) and these become milky white with age and eventually need replacing.
Finally, a pre-purchase inspection by an expert is advised to check the car hasn't been crashed and badly repaired.