Possible Clues:

• Disruptive competitor forming attachment to racing car
• Flap putting brake on pre-emptive story
• Sore lip (anag.)
• One vandalising part of car
• Aerodynamic surface on car
• Almost ruined front of racing car's aerodynamic fixture
• '68-Across is DYES,' for example
• Movie reviewer's no-no
• Disclosure of plot to overindulge head of state
• Overindulgent type who gives the game away