First off, even though you didn't ask for an opinion on the lift, 12" is well into the stupid-high category. No flex and it'll ride and handle like a brick on a roller skate. Not to mention the poor driveline angles and steering problems. That being said, most 12" lifts will come with 8" springs and 4" blocks.
<font color=green>Evan</font color=green>[img]/wwwthreads_images/icons/crazy.gif[/img]