Install Ultimate Backup and you can edit the defaultregions.xml under Plugins/lspsdfr/UltimateBackup
Install EUP L&O, EUP Menu, and EUP Configurations
Please elaborate
If you are asking about vehicles I would recommend going to the "Vehicles Models" tab on the downloads page and sorting by most downloaded as there is far too many amazing models to recommend just one. Also what I think looks good is probably different from you so I recommend just exploring and finding something you like. With that being said TickleMeElmo's Pack. If you are looking for plugins then Bejo Ijo, the same author of the aforementioned Ultimate Backup, creates and frequently updates his plugins. For lots of people myself included his plugins are an absolute must have.
I hope this somewhat answers your questions but if you would like me to explain in more detail just ask.