Do I need adhesive or suction cups to mount this?

Mounting method isn't specified in the product data. Test-fit the mirror first against your windshield or dashboard before committing to adhesive or suction hardware. Most universal mirrors work with either method — choose based on your preference for permanent vs. removable install.

Will this replace my factory side mirrors completely?

Not completely. This is an additional wide-angle mirror that supplements your factory setup. Install it where it gives you the best panoramic view — center windshield, upper dash, or passenger side. Use it alongside your OEM mirrors for full coverage.

Does this mirror distort the image like some wide-angle mirrors do?

No. The flat mirror surface gives you true-to-distance reflection without the bubble or curve distortion you'd get from a convex wide-angle. What you see is what you're actually looking at.