Shocks/struts don't have a 'sweet' spot. The damping rate is generally linear at all points along it's travel. Fancy off-road shocks will have position dependent valving, but our vehicles certainly don't.
For motorcycles/bicycles/ATSs/UTVs, sag (the amount of bump travel from full extension to ride height) is ~25-35%. I'm not sure what is for cars (which is the point of this thread ), but I'd think it'd be below 50% since you want more bump travel than droop travel to soak up the bumps on the road.
Lots of tuners do lots of stupid things (I'm not implying Aerocoupe 's tuner is stupid).
Deleting the rear O2s is common (in applications that have them), as they don't affect performance/drivability - they just let the user know when the cats dead.
Nobody even knows their O2's are out of range unless they test 'em....or a new(er) vehicle throws a light or code...
The front O2s in closed loop (>99% of time spend driving) help fuel efficiency, drivability, and emmissions. As long as the trim is +/- 25% of nominal, the O2s can get the AFR back to stoichiometric for good fuel economy without bucking.
Going Open Loop 100% of the time is generally a strategy used when properly tuning the vehicle is too hard or time consuming. Instead of really nailing down the MAF table or SD tables, you can specify OL 100% of the time, richen the mixure a bit over stoichiometric and just take the mpg and emissions hit.
Aerocoupe might have some insight as to why his tuner went full OL tune, but I've never seen a good reason (for me) to go that route.
He made two more pulls and came back inside and said he deleted the O2's from the EEC so I can now unplug them and plug the holes in the X-pipe. Said the signal on them is usually crap and he can tune without them and the signal on mine was crap.