The workmanship, from what I can tell from the pictures, looks fine; it's the design and concept that haven't been thought through. For instance, look at the rear end: the trunk has a nice curve in it, and so does the original bumper cover, but this person has chosen to make a flat bar straight across which doesn't fit the design language of the rest of the car. Same with the wings. The headlights were sized for a much smaller car and are out of proportion. There's too much overhang in the front, the wheel arches are misshapen, there are redundant hood scoops, and it has a very pronounced beak or proboscis.
Lastly, the $75,000 appraisal is a joke, unless it was done by a blind guy.
Those other vehicles you posted at least have a cohesive, coherent design language; this looks like it was cobbled together in someone's backyard--which it was. That also explains why, a month after posting the ad, the car hasn't sold, despite the "Lambo door hinges" and "Cadilac [sic] tail lights."
Edited to add: I'm not trying to belittle the guy who made this in any way; he obviously wanted the car this way and I hope it makes him happy (or not--maybe there's a reason he's trying to sell it?). I simply found it amusing that someone would go to as much or more trouble as we Ecomodders do to alter the look of a car with no thought given to its functionality; rather than hideousness with a purpose, like most of us have, he ended up with hideousness for its own sake. As an artist myself, if that was his artistic goal--I can respect that.