Had this same dilemma myself recently.
Went with cryo-treated, slotted rotors from Powerslot. Pads are Hawk HPS, ATE Super Blue brake fluid (same name cast into your MINI's caliper
), SS lines from Goodridge.
I followed directions for bedding in the pads/rotors, but haven't recorded nearly enough miles to have heat cycled them properly. So am taking it easy until then. Its supposed to take 200 miles or so until they bite well.
Despite some aftermarket brake rotors or pads being suspect I can't see you going wrong by changing to ATE super blue, or if you don't mind more frequent maintenance (flushes) Motul RBF 600 will handle even more heat. Dissipating heat is the real issue.
Installing a set of SS lines and the Mintex or Ferrodo pads also offers improved pedal feel and stopping ability. Although I didn't get them I've heard that the Ferrodo are some of the best.
Something else that I've seen which is supposed to improve both feel and performance is a brake-caliper stiffening kit. The kit replaces the OEM rubber caliper bushings with brass. This modification requires more maintenance - anti-seize each time you change pads, or at least annually. The benefits are less caliper flex/torque & more even pad contact with the rotor.
Hope you get what your after.