The X version of Live for Speed brings a lot of improvements:

- Preload added to clutch pack differentials improving handling
- The number of cars that can join a race has been increased to 32
- False starts are now possible (LFS does not hold you at the start line)
- Skin improvements including high resolution premium skin download service
- Global class balancing system (currently applied to GTR and TBO classes)
- A new version of InSim including many improvements and a button interface 

Sounds pretty cool. If you need more details regarding the new version visit the link .