As on the Elise S1, S2, and S3, the Exige V6 also came with water radiators which have plastic tanks.
Although there’s not much wrong with the tanks on their own, the position of the radiator causes air bubbles living in the top of the tanks which cause temperature stress on the plastic, ultimately failure.
Mind you, the early Exige S manual had a different kind of radiator, the type we call ESUNIRAD.