No prob Matt. The brakes are based on the std 1200 hub. Just a minor bit of machining required for fittment. Outer diameter of the hub needs to be machined so that the s13 rotor sits over the top, unlike the std 1200 rotor which bolts on from behind. The snout of the hub also needs to be machined also to match the ID of the S13 rotor. couple of MM's tops.
As for the caliper, a mounting bracket needs to be made. The bracket is bolted to the 1200 orginal caliper mounting points and then the S13 caliper is bolted to the bracket. no slimming required. All components line up. All bolts can be reused, 1200 caliper bolts to mount the bracket to the struts and the S13 caliper bolts to mount the caliper to the bracket. Also re-use the S13 wheel studs [as they are longer] in the 1200 hubs.
This convesrsion could't be easier..
The same bracket applies to both versions of the S13 brakes offered from the factory.