The 2007 Canadian F1 race sold out at 120,000.

2009 MotoGP Indianapolis - 3 days: 146,680. Sunday, 75,130
2006 MotoGP Laguna Seca - 3 days: 151,000. Saturday, 48,500; Sunday, 51,000
2005 MotoGP Laguna Seca - 3 days: 153,653. Friday, 40,520; Saturday, 55,201; Sunday, 57,932

I don't think that Austin has ever held an event with that much attendance.