The version mentioned, v0.26.1, is the polished version of the major Autumn 2022 release.
The specific ".part4" file likely refers to a split-archive of this 88MB update. Key improvements in this patch included: BeamNG.drive v0.26.1 Release Notes BeamNG.drive.v0.26.1.part4.rar
: The iconic hatchback was completely rebuilt with high-fidelity textures, improved body proportions, and approximately 40 new configurations . It introduced a mid-engine, rear-wheel-drive MR Turbo variant inspired by Group B rally cars. The version mentioned, v0
: A long-requested graphics feature that added a realistic sense of speed. The version mentioned
: All cars (except the T-Series) received animated manual shifters , and many now featured functional odometers and openable doors, hoods, and trunks. Key Fixes in the v0.26.1 Hotfix