Trigger Rally 0.6.0 for Linux (source portable) brings following new features:

• New (and old) contributed tracks and events
• New Practice Mode
• Paging on the Single Races screen to show all the available tracks
• Option to show speedometer in KPH or MPH
• Option to show digital speed on the speed dial ('hybrid' style)
• Fading track comment and GO at race start
• Freezing course time when passing through a checkpoint
• Tweak menu colors for more contrast

PS: If I understand this tweet correctly, this means high-quality motor, drift and crash sounds for Speed Dreams that hopefully will also be usable in Trigger, SuperTuxKart and other racing games.