No...they are not all that much use for the average guy. Motorhead Mike will come along and tell us that his works fantastically and how to set yours up
In the end, we tune for the leanest a/f we can get without incurring detonation. There is no correct number as it is driven by drivetrain combination and ambient conditions.
Therefore, we just remove as much fuel as we can without having timing retard and call it good. On the street, I add a couple of percent back in.
Now, if you had a very sophisticated chip or aftermarket fuel management system, having a wide band for tweaking specific functions might pay off at the track but on the street, I have not seen any benefit other than it gives you something to talk to your buddies about when drinking a cold one.
I have seen a couple of guys that had a good a/f number because they kept adding a little more alky periodically until the fuel pump was almost dead before they figured out they were adding alky to compensate for a bad fuel pump. For some reason you almost have to hold a gun on a guy to make him check fuel pressure these days in some cases.
