Just my two cents worth, I'd say the hell with California, hopefully you don't live there. If you do cheapest fix may be to move and skip the dpf / egr problem altogether. Probably could save some money on taxes also.
If you haven't seen this, check out post #1....... http://www.thetruckersreport.com/tr...3-cummins-isx-cm871-technical-discussion.html
Even though it does not apply to me anymore, that thread is very informative... thanks... CAT Now im trying to find a thread similar for the DD15... Any thoughts/links?