As I continue to research various options, I come to discover more interesting and possibly problematic things. One such is the possibility of having to use premium in a supercharged 5.0 L. Is this a must? I read that if you did, you would need to retard the timing so much that your fuel economy would suffer greatly (and would offset the fact that you save a few bucks filling up with regular). Is this for sure? I want to be able to run my 5.0 L on regular but I don't want this to happen. Would it be better if I used less boost (6 psi to 10 psi) and then only used premium (and more timing) if I went 10 psi +? Thanks for your input