In search of replacement wheels, I encountered some wheels with +20 offset. If it is 16 X 7, will it stick out of the body? The rear may still be all right, but I worry about the front as the gap between fender and tire is less than the rear end. But then, 15mm is not much. If it can take 35mm, maybe 20mm??

I also want to know the difference between 35mm offset and 40mm. It is only 5mm which is about 1/4 inch. Will the result drastically different if I get 16 X 7? Has anyone tested this kind of things??

20+ offset? where did you find these? Most of the wheel fitment guides and recommendations/experience is for xBs, but maybe something can come of a bit of experimentation. Your assessment of what the offset measures is correct, the difference between a 30+ and 35+ would be 5 mm. But also I'm sure measurements and real world application may vary between manufacturer and even within the same make.. let us know, and do you have a link about the 20+ offset wheels? I'm curious myself

I found TSW Rib with 20+ offset on Discount Tire Direct Web. I wish I had some ways to experiment differnt offset wheels on my xA to see how they look. Unfortunately, I don't have ways to do it. There are many nice looking wheels with 40+ offset. I found some wheels with 35mm offset, but they don't look as good as those with 40+ offset.

there is a tool that you can put inside a tire, then play with different offsets on the car. I saw it on a show on spike tv.

Yeah, I have been thinking about the use of spacer. I saw xB with spacer at the Halfmoon Bay get together. Personally, I am not hot about it. I will make the decision soon, though. Going for the design I like or not.

i couldnt find a link for the tool, but heres some info to help figure out what will fit.
http://www.mtdealer.com/ph_dimensions_2002.cfm

16x7, +20mm should not stick out of the body. The front will be just RIGHT inline with the fender lip, and the rear will actually still be in a couple mm. If running that size wheels, I'd recommend a 205 width tire. If you don't mind going with a staggered wheel setup, get +25mm in front, and +15mm in back. That's assuming you stick with the 16x7 wheel though.