What's the name of this Pep Boys type item we used buy when I was a kid that inserts into the coil spring and contracts the coils together with 2 long bolts? Can I still get these and use them to lower my rear springs ride height a 1/2 inch?

They are still out there.
http://www.jcwhitney.com/autoparts/ProductDisplay/s-10101/p-1117/c-10101

Auto Zone has them, too.