Ah an 04 perfect sense now.
You will be very happy with the super charger, and if you get the mysterious power loss take it in and have them look for a Knock Sensor code. The SES light will not come on if it fails, and it makes a huge difference when replaced.
Premium fuel is a must also, I ran it both ways and there was a difference in performance between the two.
Get used to the difference in power and you will be very satisfied.