Originally Posted by Bullitt@UAMotorsports

With a +22 rear you will need a 20mm spacer or more to get that same look. Spacers lower your offset rating i.e. a 20mm spacer will take your offset rating from a +22 to a +2 and so on...

The lower the offset the further from the car your wheels sit.

For example:

-a "1" represents your fender
-a "-" represents # of offset
-a "0" represents the outside edge of your tire
-a "I" is the inside edge of the tire

so with that legend lets look at a +22 setup:
____________
----------------1
--------I----0


Now a +0 setup:
____________
----------------1
----------I----0


and a -10 setup or similar:
____________
----------------1
-------------I----0

As you can see the lower in offset you go the further out the tire sits...

I hope this helps you and others understand a little more without going into the heavy details...