Complex sentence: Just before they won a talent contest in Limerick, Ireland, they changed their name again, for the final time, to U2 at a farewell concert for Dik Evans, becoming the 4-piece band they are today.
Split into simpler sentences: Just before they won a talent contest in Limerick, Ireland, they changed their name again, for the final time, to U2. This was formally done at a farewell concert for Dik Evans, becoming the 4-piece band they are today.