For those still desperate to blast music over their Big Rigs: Over The Road Racing speedruns, Twitch has now introduced a new royalty free Music Library. I've already checked. Sandstorm isn't there.
Instead, you can find over 500 songs deemed safe for use during streams. You can find details of how the system works over at the Twitch Music FAQ.
In addition, Twitch is launching dedicated music streams onto its service. You can find the current crop through the Twitch Music beta page. If you need a fun distraction, see how many clicks it takes to arrive at random dubstep.