I replaced front rotors, calipers, pads at 40 mph I still get brake vibration.

Just a note: 'Proper' lug nut torque and torque sequence critical anytime wheels are removed/installed to help prevent this type problem.

Loose tie-rods? IF answer #1 is NOT the issue? Inferior quality or improperly stored brake rotors? Used to work with a guy who ALWAYS resurfaced brand new rotors because he said they'd always be warped(He always got the cheapest /lowest quality parts!!

Phase match the rotors to the hubs. Better yet use an on car brake lathe.