Will this work with my 3-inch lift kit?

Yes. This arm is engineered for lifts in the 2–4" range, so a 3-inch kit is right in the sweet spot. It corrects the suspension geometry that stock arms can't handle once you raise the truck.

Do I need new ball joints or bushings?

That depends on the condition of your current joints and bushings. If they're worn, now is the time to replace them — the control arm install gives you easy access. If they're good, the new arm will work fine with them.

Can I install this myself, or do I need an alignment after?

Installation bolts at factory mounting points with basic hand tools. An alignment is strongly recommended after any suspension work — new arms and lifts both change caster and camber angles, and alignment ensures even tire wear and proper handling.