The turbo timer isnt hard at all to install...Just be careful when removing the parts of your dash and center console so you dont scratch them. I used the scooby mods install instructions and worked it like a charm Turbo Timer Install
Sooo easy with the harness...I have an '03 and I used the '02 harness but i dont know about the '04. On the scooby mods website, they tell you what to do for a 4eat. With my factory alarm, all i had to do was cut one wire and tape the ends and it works....Once again scooby mods will tell you which one..just click the link. I have the Greddy Full Auto and I like it a lot...Beside the fact that it only cost me $89, it has numerous features besides the voltage meter. Have anymore questions, let me know...I just did the install like a week after i got my car not knowing anything about the car...Really, Really, easy install with the harness.