the Cost of those AP racing disc assemblies for the R32/S3 was the seed that became the NQSBBK.
Don't expect any change out of £750, with AP Racing its all about volume. Ready assembled disc assemblies carry the LEAST amount of margin for dealers hence nobody stocks them and AP doesn't bother stocking them either.
Last time I asked there was one set on the planet and they'd only ever sold 3 sets in 5 years