If you log, you can check stuff like what actual timing you are leaving with. So if you are commanding 28 timing WOT, you'd want to verify you are leaving on that.

Converter sounds tight, if it's just at 300, but then again a 01 C5 is not super heavy. Probaby a 2.56/2.73/3.15 gear out back?

What is the RPM drop on the shift? 600 is race car and 1500 is tight.