The SLRR engine is notoriously fragile. To avoid the frequent "game crash": Street Legal Racing: Redline v2.3.1 - Steam Community
This is debated among veterans. supports thousands of mods (including tracks and complete overhauls) but lacks modern updates. 2.3.1 is more stable and actively updated by ImageCode but has limited mod compatibility. Many modders maintain separate installations of both versions. Street Legal Racing Redline V2.3.1 Mods