Will this bolt directly to my engine bay, or do I need to drill new holes?

This tank mounts at factory rocker and bracket points — no drilling required. Use the existing mounting holes and fasteners from your original tank.

What fasteners do I need to secure it?

Hardware is not included with the tank. Reuse the bolts and clips from your old tank, or pick up universal mounting hardware from the fastener aisle if yours are corroded or missing.

Does the white finish need any prep or paint before I install it?

No prep needed. The white finish is ready to bolt in. If you want a different color, light sanding and spray paint will stick without primer.