I can vouch for the RS Spec Bilsteins (off a 2001 model). I have had them for about 18 months and wouldn't change them.
Originally I had the factory RS springs and they were
really hard but still quite liveable for me at least. I think they would be harder than the Kings though (which can be rough themselves, I have only experienced them in an NA). With the weightier 17's that may not be a bad thing I guess. Personally I run 16's. Kings come in different heights as I understand. Lower will mean some scrapes yes - all part of the fun
. As long as they are not too stupid you should be ok. Some say Kings can sag over time, others say no.
FYI I now have eibachs which I think are a little better matched to the RS specs (as do others that have drĂven the car).