Corsa is more performance-oriented than a Rex. Two big wheels (700c or 650C) means a higher bottom bracket resulting in a more aero position. Images show that most have hardshell seats. Between the seats and the high BB, a more-reclined position is common compared to the Rex. The Rex is a great do-everything bike. Probably easier to learn to ride than a Corsa but that bike would be worth the effort if you care about going faster.
In 2008, a new V-Rex LE sold for about $1500.