the cat may have power droops off and the isx on ...I removed the fuel saving programming off my isx 450 .and it will make a cat seem like a crawler now
take the lbsc out of the isx and remove the power droops ...guess some people don`t know that ...both engines have amazing potentials
Go with the Cat.NO EGR. All others 04 and later do. EGR puts a lot of soot back into your motor. I have heard ALOT of EGR engines are being overhauled really early. Plus they have a lot of problems that are very difficult to diagnose, especially cummins. As long as you don't buy 08 or newer you won't have to worry about dpf either.
Despite not being as good as the E-model Cats, the ACCERT engines are still pretty stout. The shop that has my truck right now (doing an in-frame) works on a lot of Michigan loggers truck that haul big loads and need big power. They routinely pull off the twin turbos on the ACCERT motors and replace them with a single turbo of their own specs... the loggers like those changes and they keep the repair costs down compared to an ACCERT set-up.