I went to another mazda rev it up event again in irvine today. I checked out the 2003.5 mazdaspeed protege again and here are the differences that I have not mentioned before. The piping is not aluminum and is rubber just like the 2003. There were assumptions that were made before of aluminum piping but the production ones are rubber. In addition, the spring rate on the clutch is different on the 2003.5 than the 2003 and the clutch on the 2003.5 is a lot stiffer. They actually got the information later in the day. They said that the clutch will last longer and less slippage but won't really affect the performance of the car. We all know the other differences: front lip, gunmetal rims, mazdaspeed knob, mazdaspeed pedals, larger muffler.