So apparently, DNA Designs has an upgrade kit for Legacy Prowl:
BigBadToyStore has a massive selection of toys (like action figures, statues, and collectibles) from Marvel, DC Comics, Transformers, Star Wars, Movies, TV Shows, and More
www.bigbadtoystore.com
It looks really cool but once again, it's like,
the exact cost of the figure that it's supposed to be upgrading. I'm not sure that I'm seeing fifty-plus dollars of Prowl when I look at the finished product, but there it is, for those interested.