any one running the Torq-Thrust M 17 or 18 inch wheel on there 68-70 charger

[1st_charger]

I've been looking at the Torq-Thrust M from American racing for a wile now and was wondering if anyone had them on there charge,r right now I have 275/60/15 on the rear and 245/60/15 on the front and I like the way the car sets! I would like to go to the Torq-Thrust M in a 17 but keep the tire diameter and width. I would even consider the 18's for the rear if I needed to in order to keep the diameter the same. I have been looking at tire and wheel web sites so much I am starting to mumble in aspect ration, so i thought I  would ask here and see if any one knew what would fit and were it would be available. I have not measured for back space and off set yet so if you want to chime in on that also I would greatly appreciate it!

Thank you very much