Most people recommend starting at 32 PSI with radials, and then working up and down a pound at a time to experiment, but never going lower than 28 PSI. Radials need proper air pressure to maintain their footprint on the track, and if you were to lower the pressure to 18 PSI (like a drag slick, for instance) the center of the tire wouldn't contact the track and would cause stability and safety issues as your speed climbs.
It sounds like your on the right track with removing some dead weight. Other things that can help is only having as much gas as you need to get to the track, race, and get home safely (gas wieghs almost 8 lbs/gallon).
If its your first time at the track, I wouldn't worry much about putting ice on the upper intake or anything. Just concentrate on driving the car fast and consistent.
Also, you don't need to do a burnout with street tires. All it does is waste tread life. Street tires don't need to be heated up like a drag slick. Avoid the waterbox if you can, and just spin them lightly to clean them off. This worked for me to the tune of a 2.17 60' time, which I didn't think was too bad with 225/55/16's.
Also, watch the tree carefully. Don't wait for the green to come on to take off, lauch when the last amber bulb is on. The time it takes for your brain to react and for your car to break the stage beam will make up for it. Most of all, have fun!
