Dry ice blasting is not too common on autos from what I have seen. It will do little to nothing to rust IMO, so you might as well use soda, walnut or plastic media which also does little to rust but is likley less expensive than dry ice.
Dry ice is typlically used for mold remediation (do not want a bunch of blasting media all over the inside of a house to cleanup) and for cleaning carbon deposits in heads and for tool and die cleaning where you do not want any grit.