You will not feel a difference with the plugs...I didn't anyway.finally got plugs done - took them 2.5 hours and got them to fit JB4 too - yay. Still need to do more miles though so I am resisting.
Interesting to note the default setting once you connect to it is to set it to MAP 1. Set it MAP 0 until I've got some more miles under my belt.
Is it possible that just plugs will make it more peppy on their own or is it just loosening up?
I waited 1k miles before I started using mine.
So...the shop ran the ODBII cable for you...to the JB4 unit? I put 3M velcro on the bottom of my JB4 and it sits on top of the fuse box. I strapped the Bluetooth unit to the JB4 with some velcro straps.