Muppet Question? E92 Winter tyres on Z4?

[Twin Turbo]

Hi,

Since the winter is coming, and I believe my alloys of my E92 are out at the front - but i am no expert.

Z4 Orginal
Front alloy wheels: 18x8" ET29
Rear alloy wheels: 18x8.5" ET40

E92 Winter Alloys
18 x 8.0" ET34

I understand that:
Front: Compared to your existing wheel, this new wheel will have an inner rim which is 5mm closer to the suspension strut. The outer rim will poke out 5mm less than before. So I need an 5MM spacer?
Rear: Compared to your existing wheel, this new wheel will have an inner rim which is 12.4mm further away from the suspension strut. The outer rim will poke out 0.3mm less than before. no issues?

 

[mmm-five]

5mm shouldn't really be an issue.

Will probably get away with standard (non-m) 225/40/18 on the fronts and 255/35/18 on the rear.