From The Rules on the Home Page:
Vehicles with T-Tops or moon roof panels shall have the panels retained with tabs or straps.
This is for 2011 ONLY!:
All vehicles over 250 MPH shall replace all non-laminated safety glass windows with polycarbonate material. All other glass, such as headlights, must be covered with SAFETY film.
Beginning January 1, 2012 all vehicles in classes where the record exceeds 200 MPH must have all non-laminated safety glass windows replaced with polycarbonate material.
Beginning January 1, 2012 all vehicles with “frameless” side windows, regardless of speed, must have all non-laminated windows constructed of polycarbonate material.
Additional bracing must be installed to prevent window blowout or collapse.
Added from 2010 rulebook, in effect for 2011: