Comparing the 2003 Courage C65 (top) designed to LMP675 aerodynamics rules to the 2004 Courage C65 (bottom) designed to the new LMP2 aerodynamics rules.  The Courage C65 chassis had originally been designed with 2004 LMP2 rules in mind.  A synopsis of the '04 LMP1/2 rules is here.  The primary difference '03 to '04 is the rear end aerodynamics and the underbody.

Again, a back to back comparison of the '03 LMP675 C65 and the '04 LMP2 C65.  The visual effects of the regulations changes are more evident in these head on shots.