Are you asking for a recommendation of brands for coil spacers? This is not one of those decisions you have to sweat over. Figure out how much higher you want to be and buy the appropriately sized spacers. I'd pick the cheapest.
Your pic shows zero percent of the components. Procomp is pretty budget so I assume no adjustable arms or trackbars? What backspace?
Sagging as in riding on your bumpstops or tires occasionally hit the front bumper when dropping off ledges at full stuff?
Spacers will lift you. If you flex out now without ripping and brake or sensor lines that won't change. Not adding shock or coil length just means you sit higher into your usable travel.
Consider your suspension as a whole. (Not just a money hole but as a whole unit). Raising your center of gravity for appearance is a questionable decision.
Considering the AEV or Rubicon Express 4.5 in the future for a better lift, at only 3K, it's def worth it. No other components were added with this lift besides what came with. Just looking to make up for what the extra weight will add for right now.
As stated above all the spacers are pretty much the same. Spend as little as you can.
For a future lift I think you could get better lifts. Consider Synergy, Rock Krawler, and Metal Cloak. Everyone tends to recommend what they have.
If I were going to drop 3K on a new lift I would be looking at this Metal Cloak 3.5"