Offset difference

[Harpham]

How much difference does offset make?

Standard OZ F1s are ET43 iirc. Looking at some 2118s that are the cup racer offset, which is ET48.
Will this make a real difference to the stance on my car, as I'm running spacers all round and the arches are currently nicely filled.

Any info would be muchly appreciated.

 

[deer_dodger]

wheels will move in 5mm each side. Possibly not noticeable tbh