Yes, brad is EXACTLY correct.
An offset is just what it means, offset. Having a + rated offset means that the wheel it's self, after divding the size of it in HALF is that much more IN towards the wheel well. The same holds true for a - offset, only the wheel sticks more OUT from the well..
In your case Badger, your wheel is a 16x8. This means that the wheel is 8 inches wide, and that RIGHT in the middle of those 8 inches is where the wheel contacts the axle. That means 4 inches out sticking outwards from the axle, 4 inches sticking inward towards the axle. From there, having a 0 offset. (IE: +/- 0 mm) Means that the wheel does not further stick in one direction more than the other after it contacts the axle.
I think that with the lift you have and the wheels you got, you'll be JUST fine an have no problems with any rubbing. I have 16x8 wheels also with a +12mm offset, and only a ONE inch lift on the front of my ST. My wheels don't rub at all unless I turn the wheel HARD in one direction or the other, and then they still BARELY contact the wheel well... So again, I think you'll be just fine. Check out my pics in the "MAR 06" folder to see how the offset looks.
~Josh