The wbx motors are low octane happy, true, but I'd guess there are a
significant number of us who have ditched the stock motor for other power.
Most engines have some method to prevent continuing pinging, which is a
harmful running condition of running low-grade gas.  So one can run low
octane fuel, but your motor will have to compensate with it's anti-knock
system, with a less performance ignition setting, etc.

It would be interesting to test a moderate compression motor on regular,
then premium to see if you save by using regular in a motor that has been
designed for higher octane fuel.  I know my Jetta hybrid, which has a high
comp. ratio, it runs just fine on Reg. Gas but it makes noticeable more
power on mid or prem.

As for Stabil gas treatment.  Ethanol gas is nasty stuff, it "goes bad"
very quickly, and it keeps getting worse till you can end up with
car-killer goo. I recently restored a couple of bikes and every rubber
o-ring and gasket was shot..useless.  I had to discard one fuel tank,
nothing would disolve the ethanol residue.  I try now to run just a little
Stabil in all my motors..