NASCAR 2003 Replay Analyzer
It is a program which loads up your replays and analyze/compare driving lines.
What is N2003 Replay Analyzer? In short - it is a freeware program with which you can load up your NASCAR2003 replays and analyze/compare driving lines and different kinds of "telemetry" plus generate race and practice reports and a bunch of other statistics.
Furthermore you'll find lots of different tools and features in N2003 Replay Analyzer, explore the menus on the left to find out more about them.