I've done just about all of my performance mods to my car after installing the stereo. This includes headers, intake, exhaust, and nice plugs and wires. The stereo, i'm guessing, weighs at least 400 lbs. My car is not all that fast now with the stereo. I remeber, when the car was stock, it seemed faster. That is without the extra weight and without the mods. If i dropped the stereo, would this car be a lot faster or not? Dumb question, but just curious. It seems to have great pickup going downhill at around 60-80mph now. Approx. how many horses will the headers, exhaust, intake, and expensive plug wires give the stock Si motor? From 106 to around 115 maybe? I've read where the headers add the most.