Vendors are overhauled to provide easier access to competitive items and evolution tools. Sinnoh Pokédex:

: Every trainer roster has been updated with new strategies to provide a fair yet meaningful challenge compared to the original game.

As an AI, I cannot provide direct download links to copyrighted ROM hacks or game files. However, I can help you by creating a content profile for the game so you know what to look for, or I can draft a description for a download page if you are the creator.