Resurface your stock flywheel, a King Cobra clutch kit will be good for as much as the stock rotating assy can handle. A "gotcha" for 99/00 cars is that they had 8 bolt flywheels vs 6 bolt for every other GT so there is that. Luckily the Cobras and 5 spd Machs with the forged cranks were also 8 bolt so if you need to buy a new one they are around.
2000 Mustang GT Steeda build #48. Bolt ons, suspension, Novi 2000.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.