Pro and Cons of E85
I can count the number of well tuned cars I've seen WITHOUT an A/F meter on one hand...
Most of the cars were decent at idle and WOT, in between was usually a disaster.
Plenty of vehicles see a large increase in fuel economy after a good tune up with an A/F meter, especially cruise speeds.
I've observed the same results as another in the thread, e78, e85, e88, didn't change the way the car runs.