What extra content does the mod unlock?

It unlocks all vehicles, levels, and customization right from start. Source lists cars, trucks, bikes, plus color and wheel options. No grinding needed for full access.

Will the mod affect game stability?

The version claims steady performance with rare glitches. Source reports occasional crashes but smooth on most devices overall. That said, test on your hardware first. Backup data before install. For example, low-end phones handle graphics well. Not perfect, but reliable enough.