The answers to the starred clues are the first part of band names with numbers in them: MATCHBOX [20]; MAROON [5]; JACKSON [FIVE]; and FINGER [ELEVEN]. When you add the missing numbers together, as suggested by the clue to 60-Across, you get a SUM of 41.
The band Sum 41 had four songs in Top 10 of Billboard's US Alternative charts between 2001 and 2004: "Fat Lip," "In Too Deep," "Still Waiting" and "We're All to Blame."