I am looking at some wheels that are 20" x 8.5" with an offset of ET13. I'm not sure if these will fit correctly. I know the 20 x 8.5 is correct, but what does the offset of ET13 mean? I thought I remember ZX posting the the stock wheels have a +31 offset.

 

Can anyone help me out with these wheel offsets. Need to know the difference between the current +31 and ET13?
Thanks