This is a non-exhaustive list of changes. Check the Steam event for more details.
Many new vehicles, including motorbikes.
New locations and NPCs, and new content in existing locations.
Vehicles are now moddable -- find a mechanic near you and bring cash.
New system for garages and vehicle security.
New system for finding lockups in the slums and converting them.
New system for vehicle wear and maintenance.
Plus a load more.
New equipped effect for very high ambient temperature.
New artwork.
Fixed some more typos and bugs; thanks for the reports.