Thank you,
these wheels only come with an offset of 30 in 5x100 configuration. This translates to a backspacing of 5.68" (according to online calculators).
As a side story I've now had an "ah ha!" moment on offset vs backspacing. As we know offset is just how far offset the mounting face is from the center-line of the wheel. Backspacing must incorporate the actual edge of the wheel and not just the advertised width (which is NOT measured!!!). This is why the backspacing on a ET30 wheel is 5.68 and not 5.18. Maybe i like backspacing now instead of offset. It is easier to understand how the wheel will actually fit.