That refers to your Speed IV and nature.
In general, you read that notation as (negative nature / neutral nature / positive nature).
(31- / 8- / x) means: 31 IV or less with negative Speed nature (such as Quiet Nature), 8 IV or less with a neutral Speed nature (such as Modest), and never with a positive Speed nature (such as Timid).
As a side note, this specific shopping is done so you will have enough X-Speeds to use even if you get Rock Tomb on Gordie.
Also, if you aren't exactly tracking your IVs, always assume the worst :)
Turbo is now allowed for all categories in the Let's Go and Sword/Shield category extensions leaderboards!
Turbo is a function that allows some 3rd party controllers to input repeated button presses by only holding the button down, i.e. holding down the A button would simulate repeatedly pressin