Complex sentence: A further enhanced Challenger 2, dubbed the Challenger 2E, was planned to enter service in other foreign nations, notably Greece, but did not perform as well as a German counterpart, the Leopard II, in the Hellenic Army's competition for a new MBT.
Split into simpler sentences: A further enhanced Challenger 2, dubbed the Challenger 2E, was planned to enter service in other foreign nations, notably Greece. However it did not perform as well as a German counterpart, the Leopard II, in the Hellenic Army's competition for a new MBT.