Mini and STP 5 in 1

[Deafjeff]

Hi,

I’m about to buy a used Mini Cooper S 66 plate 21K on the clock. I got STP 5 in 1 to give it a good clean (just in case)

I have been trying to find out if I should also use premium unleaded petrol or standard will be fine given that I will be using this additive.

I have been trying to find an answer on website and it just said ‘fuel’

For those who have used this what did you do?

Thanks