I have an 05 545i with sport suspension..... Currently I have stock sport springs with 166 m5 wheels 245/35 fronts and 285/35 rears ...with no rubbing issues at all

Want to put a set of Eibach springs on and was wondering

1) if anyone is running the same setup with same tire size
2) do I have to change tire size because of rubbing
3) some people say eibach only lowers about 3/4" so is that true or does it lower car as advertised

Any info would be much appreciated

Thanks