I've got threaded NB perches developed and coming in the next two weeks! These will work with the open-end style 3.25\" spring used on the 99-05 and is available as an adjustable spring perch. You can use FCM sleeves on Bilsteins, Konis, or KYB to give you ride height control. For those running MSM (SE) or Hard S Bilstein on your car and loving the ride but hating the look, you can add these to get the height down.
These are truly custom (and take a lot of CNC time to make) so don't expect steals, but they'll serve a need in the community and as the machinist said, they were cool to develop I expect sale price to be about $40USD per NB-style perch. First batch is of 50 or ~12 sets. Photos of the unfinished parts are attached.
EDIT: The final pieces will constrain the springs better than the prototypes shown.
What do you think?