lol, firstly, adjustable arms DO NOT increase NVH, not the adjustability at least, it's only when the arms use rose joints on the ends, as u basically removing a flexible bush, its now metal on metal. the adjustability comes usually from a turnbuckle where a solid arm would usually be. you can buy adjustable arms with with urethane bushes, so they are exactly the same as adjustable bushes as far as NVH goes.
whiteline themselves make adjustable arms, after starting with adjustable bushes (f**king useless) i know exactly how much better adjustable arms are. also as a side note, whiteline bushes are shit lol. i run their arms, but the bushes are shit, mine cracked and split with less than a few weeks on them lol
2ndly, less castor, why? i can only think of 1 reason, u have bitch arms and cant handle the weight of ur steering