Not a fan of the JE Design one, looks very stuck on.
Definitely the Seat kit's the way to go, just buy two normal cupra honeycomb front pieces (should be able to do it with 2) and fabricate a honeycomb insert for it. Stick with a Cupra rear bumper though.
*Edit* Just randomly thought, I have a suspicion that the honeycomb section from a cupra bumper, turned upside down, would fill the gap in an aero front bumper?