I'm not sure about the "over $30,000" . . .
I think mine has every option except the Engine Block Heater and it's just under $30K:
1999 Mustang GT Convertible $24,965.00
All-Speed Traction Control 230.00
Mach 460 Elect AM/FM Stereo/Cass 395.00
Smoker's Package 15.00
35th Anniversary Package 2,695.00
Convenience Group 550.00
Total Vehicle & Options $28,850.00
Destination & Delivery 525.00
TOTAL MSRP $29,375.00