Sparky,
I have looked at your car and there are certainly areas such as your panel joints that could be better but you make up for these possible aero deficiencies the old fashion way: HORSE POWER!!! But that being said I am SURE that you have looked at your number one, Mr. S. Hammond, competitor's new car and I am also sure that you noticed the quality of the finish on the body, not many body lap joints or other things that could trip the air. Seth has probably set the standard, as his cars normally do, for your class and to be faster you will probably need to at least meet these standards.
Changes in aero, frontal area X Cd, are equal, in affect to horsepower when it comes to maximum speed, so a 5% aero efficinecy improvement is the same as a 5% horsepower increase.
Rex