The stock brakes with Metalmaster pads are terrific on the track events I participate in. (1.7 miles, 14 corners, usually only run one lap at a time) In longer events where the brakes are used more and for longer periods, they would probably heat up. You can go to 928S4 front brake calipers and rotors with Pagid or other racing pads for a reasonable price if you use used parts. The rears don't need to be changed, just use better pads.
Yes the LSD is a separate option (either 220 or 221 depending on the year of manufacture of the car). Good luck, Bob Blackwell.