What is Sulla had not spared the life of the Young Julius Caesar?

The young Caesar, as Cinna's son-in-law, was one of Sulla's targets and fled the city. He was saved through the efforts of his relatives, many of whom were Sulla's supporters, but Sulla noted in his memoirs that he regretted sparing Caesar's life, because of the young man's notorious ambition. The historian Suetonius records that when agreeing to spare Caesar, Sulla warned those who were pleading his case that he would become a danger to them in the future, saying "In this Caesar there are many Mariuses."

What if Sulla hadn't listened to the pleas and had insisted that Caesar was to be executed? Would the life of the Roman Republic have been prolonged?