Most shops are going to recommend what they are familiar with , or the one they can make the most money off of, if you look at some of the dyno results floating around here there isn't much differrance in the results. You are not going to get a great amount of power out of this engine no matter which you choose. Most will install and play with it for a week or two and forget it is even in there. I personally got a fuel manager for the cold idle, and to richen up my fuel mix when (if) I change pipes, it (Cobra) has worked perfectly for me.I'm running the Cobra too and love it despite the shop that does my work telling me the PC5 is better. If any of you have tried the power commander I'd love to hear your opinions of it versus the cobra.