Do these headers come with gaskets and bolts?

Headers only—gaskets and bolts are not included. You'll need factory gaskets and hardware to complete the install. Don't reuse old gaskets; get fresh ones.

Can I install these myself with basic hand tools?

Yes. They bolt directly to factory mounting points from underneath. Access is tight but doable if you lift the car and remove the belly pan. A jack, jack stands, and basic wrenches are all you need.

Do I need to tune the engine after installation?

Not required, but headers work best paired with a tune to optimize fuel and timing for the new exhaust flow. Stock ECU will run fine, though you won't see full performance gains without a tune.