I do not know where that grammar came from glossaries should has and is should be know
So if I have +30 now can I switch to +20?Sorry. You are incorrect. The greater the offset, the more of the width of the wheel is on the inside. An offset of 0 would mean that the mounting face was on the mid line of the wheel,so 50% would be outwards, and 50% inwards. Anyway, pretty sure the golf is et51 as standard. Lots of folk run a 10 or 13 mm spacer, meaning that their ‘offset’ is either 41 or 38 . That still seems to work but beware of wheel width too . An extra 1/2” width will mean around 6mm further out and 6mm further in fir any given offset