If I can change the plugs in the Lightning in 45 minutes, you should be able to do the same in the '04.
What a coincidence...I just bought a set of (8) NGK TR6's this evening. I was surprised...only came out to $14.12 for all eight (Advanced Auto Parts)! I'll be doing the swap this Saturday, though. Good luck...let me know how long it takes you and anything special I should know about. It took me about an hour to change all 16 on my Hemi-powered Dodge Ram. I also have TR6's in it.
Can someone give me the plug #? I went to the local CSK and the high school nerd there just gave the duuuuuuhhhh stare when I asked for a step colder plugs. ie:supercharger plugs for a Saleen supercharged Mustang.
Yeah, they are NGK "TR6" Spark Plugs, or Part Number 4177 ($1.68/each at Advance Auto Parts). Or, just reference this list... Ford Modular Motor Spark Plug List