The type of tires that you use on the 03 will make a difference in it's handling. Iive used Pro-line sedan hawgs I know that the are old design, Pit Shumic tires 30F, 25R (sorry for the spelling) and Jaco rubber tires with good results. Here is something that you should look at when running the 03F DJ or any other 03 with the white .04 gears. The tire dia. will play key roll in your off the line and top end. If your tire dia. is greater 65mm in dia. your car will seem a little sluggish of the line. If try to keep your tire dia. in between 64mm-65mm you will find that the car has that snap that you are looking for.
These are the little things that I have found that helps me keep my 03 out in front of cars like HPI, Yokomo, and TC3's
