DPF Help

[Igor58]

Got pete 386 3 years ago, with ISX CM871. It was used with 410,000 miles on it, de-mandated, replaced original turbo at 760,000.
Found that site and after reading a lot on forum did some things that you guys advised - EGR tuneup,oil pump shimming. Decided today to check DPF canister and DOC. Remove it and not sure what to do. DPF canister got couple holes thru it, DOC intact ( no any holes, just little bit ash).
Because it de-mandated I heard that DPF must to have big hole, but what about DOC? Why it intact? And how much ceramic I have to remove - to the bare metal or just make hole 8-9 inch and leave it.
Sorry if asking not in right place.

[Cuya]

Asuming u live in country that allow u those mods I think i hear someone say for DOc make 20% bigger than pipe and 4 dpf make 8 inch open minimum. no small holes but one big hole better.

[JMBT]

If you are demandated knock it all out. There is no reason for any DOC or DPF material to be in the canister at all. In fact, if you leave any there is a risk of it breaking free and causing an exhaust blockage at some point. Plus it will sound better and should bring your EGT’s down a bit when you knock it out clean!