This thread is aging, but I thought I'd add another data point.
Here's a 993 Cabrio with relatively low miles at AIC. If he's got this thing priced below $50,000, then most 993's will be below $50k. AIC always has a premium on their cars.
993 Cabrio at AIC
I too agree that 993's in the high $40k's and low $50k's are most likely either the "S" models or very, very low mileage examples or both.