[Hoosier_300C]

I've read a lot on here about rims and keep seeing "offset" brought up for 20" and 22".

I think I've finally made up my mind that I'm going to stick with 20" for my car. I found a set I like made by Foose (Foose Speedster in Black). They are available in 20x8.5 and 20x9.5

Obviously the 9.5 is going to have the benefit of more rubber on the road, and I'm planning on going back to the stock 18's from November through March (midwest winters....blech).

So what is "offset" and how can I tell what the offset of these rims are, and what does it do.

Sorry for the st00pid n00b questions, but I'm really unfamiliar with car customizations, as my 300C will be my first customized car, I'm trying to learn as much as I can so I don't mess anything up and flush 40K down the drain....lol.