Which replacement to use?
that norms stuff is a copy of the RMS stuff only in round tube. norms used to use control freaks set up which is a bootleg copy of the alter-k in round tube. that kit in the link you posted looks slightly different then the control freak but is still basically a round tube alter-k. could just be a update by control freak. don't know. go with the original and proven one. ther RMS set up.
i don't know anyone that has used the XV set up. there was a guy on cuda/challenger i think it was that was having all kinds of trouble installing a xv suspension. not sure how that ever came out.