to be honest i would buy new discs/pads, not use ones from the scrappy.
get the calipers and don't fit them till you can new discs/pads. also consider stripping them and refurbishing them. you really don't want to fit them and find they don't work.
i had n14 brakes on my k11, big improvement over standard, GTi-R brakes were too heavy for my needs.
also, mine cost me £65 for rebulit calipers, and decent-ish discs/pads from a member off the MSC. So £100 will be more than enough to cover new parts.