Carbon Lorraine, Carbotech, or Performance Friction. Personally best performance I've experienced is Carbotech with Nitrac discs. Speak to Ian at Carbotech about your power and weight and he'll recommend which model. I ran XP8 with 150bhp and standard ish weight MX5. You might need XP10.
Track day / race car friends:
What brake pads are you using? Looking at Ferodo DS3000 or Mintex F6R but open to feedback / other options