I might be stating the obvious, but I don't see a mention so far in the thread that the SL motor is all gears unlike the belt drive normal Levo and that may be a reason for a little more gear whine.
Very mature age 'returning rider', located in the hills to the East of Perth Western Australia. So quite handy for lots of local tracks. 2019 Turbo Levo Carbon Comp with 500 and 700 batteries, so plenty of options.