hey guys i believe track is measured from the centre of the tyre, there for running crazy offset gives you wider track. otherwise i would just run 17x9 -20 offsets haha
and the 2inch oversize rule is longer its actually now no bigger then 10mm (i think) rolling diameter there for you can go from 15=20 but you have to run low enough profiles on the 20 tyres so overall its no more then 10mm in diam