Set of 4. American Racing 2 piece. Nice light weight units at about 18 lbs. Rims are in good shape and cosmetically reasonable. 300 + shipping. Will consider any reasonable offer. Pics available on request.

What's the offset and/or backspacing?

please tell me what the offset is

I measured with my trusty carpenter's level and tape measure. To the outer edges the rims measure 10.5 inches. The backspace is 6.5 inch and the offset by my calculation is 30mm.

what year and make did you use these on? Did you use spacers? If so what size front and back?

I have a 3/16 spacer on the front only because I have the LS1 brake upgrade on my 1995 z28; otherwise I wouldn't need any spacer. I have no spacer on the rears.