I've heard some bad stories about king spring super lows, and none of them are a problem of the manufacturer. They state clearly that they are for cosmetic puposes only and should not be used on the street.
Are you looking for actual performance or cosmetics? That being said, I don't really think you need to lower an RA23 more than 1-2 inches for them to look good, you're better off finding a nice set of wheels that fill out your guards nicely and give it that old school tough look.