E67 pcm on supercharged 408. Friend dropped off to have a "look" and possibly go to a blended tune. I noticed pretty quick it smelled rich while idling but wideband was bouncing around stoich. Found both collectors loose and tightened them and now im idling a full point richer according to the wideband. My question is can i make a small blanket percentage change to thee vve successfully? Anybodies input is appreciated