Here are a few tips for the 2009 SS Spring Nationals.
Try the strongest magnets that you have in you car. When the track length was shortened from 11'7" to 8'9", I took out my medium strength magnets out and put in the strongest ones that I had. Stronger motor magnets usually increases torque/acceleration, but tends to hurt top end speed.
Stretch your pick-up springs a little. It puts more pressure on your shoes and makes better contact. Be careful and don't get too crazy with it. Increasing spring pressure will cause you to have to add more lead to keep the front end down. In most cases the power increase will more than offset the extra weight you are carrying.
Try running the tallest tires that you can find. The RRR wheels are about the same size as Tyco 440 wheels. Almost any tire that fits a Tyco wheel will fit the RRR. If the tire is too wide, cut it down to size. I put a wheel and axle in my dremel tool and install a tire. Spin the wheel and cut the tire to width with a razor blade. You might need to try different height tires. Some cars are quicker with taller tires and some cars are quicker with shorter tires. It just depends on your armature/magnet combo.
Remember the max size for your mounted tires is .460 tall and .215 wide. The tires on both of my cars are .460 tall.