Need the front end loose. Moroso trick spring and a decent shock like Strange or QA1, single adj. will be fine. If the front bushings are worn and tight then, at min, you'd need to get something like the AFCO replacement bushings or something that moves free or grease them up.
Get rid of all the rubber bushings in the rearend and control arms and make it more solid. Rear uppers and lowers and sphericals will work but you will almost always need an anti-roll bar with a G-body and free moving rear suspension. And a decent shock in the back too, double adj. would be best if you're running the MT ET STreets or ever plan on running drag radials. Again, Strange or QA1 will work great there. The stock springs are fine for a while. Also, any kind of lower control arm frame mount reinforcement you can do will help keep them from hitting the floor when it makes some good power.