All you need are these lowering springs, and an alignment. If you drop the front any lower than 2" you will need the custom upper control arms off of the page listed above. I would recommend lowered shocks for the rear, new stock front shocks will be fine. but in reality the shocks you have will work. I dropped mine 3" in front and 4" in rear. Perfect numbers on my alignment print out, and handles/rides great.
I have had both lowering struts and lowering springs.
Lowering springs on the envoy i had. Lowering struts on my current ss. I like the lowering struts better..... ride is stiffer but not too stiff. And if i were you I would invest in the arms before you have catastrophic failure on your upper ball joint.
I didn't have the djm on the envoy because I didn't think i needed them. Boy was I wrong. The angle of the upper ball joint was terrible and when turning I heard a "pop" which was certainly not good. I was an idiot and kept driving it.
Do it right the 1 st time and enjoy. AND blazingtrails your tb looks good!
I'm a big fan of the Belltech system, 2" in the front and 3" drop in the rear. Whole kit is about 600 online. Eibach makes a less aggressive kit but I feel like the truck still sits too high after seeing the Eibach.