I would like to know the name of the image gallery script that www.exoticspotter.com uses.. is it a custom script?

That looks custom indeed. What I usually do to find out where a script comes from it Googling part of the URL, in this case the most significant part was "listingVehicle.php", and after Googling that I found no other links than to ExoticSpotter.com so I assume its custom made.

In deed it looks custom made, I've looked around but can't find anything that comes remotely close to it. But I'm sure you can find and adapt a similar script, jus look around for photo galleries with rating capabilities.