[0w40X1]

Ok, now I can see a few things going on.

I have the same offset on 8x18 30et and 9 x18 41 et on s28i

Front is already 1.1 inch narrower factory, and at 120 mph car would sway riithmically to nearly change lanes..

I think traction on rears was grab and throwing power to opposite wheel.

I put 12 mm spacers on front, and stopped it.

I also put less grabby cerammic pads on rear.

Your new rear offset has moved wheels out 15 mm more compared to fronts.

Put some 12 or 15 mm spacers on fronts and none on rear.

Also, those tires are too wide for 8 X18 and 9 x 18, but will maybe work it you try spacers on front first.

Perfect size is 225/40x18 and 255/35r18 or use 8.5 and 9.5.