Does the PCR product need to be purified?

No, although higher transformation efficiencies are achieved with purified inserts. If using unpurified PCR amplicons, use 1 μl or less of the PCR as insert material to achieve a 3:1 molar ratio of insert:vector. It is especially important for high yield PCR situations to avoid adding a vast excess of insert that would result in the insert ligating to both ends of the vector backbone.