Blocking the coolers will cause a CEL for insufficient flow but will still run fine.
Hollowing out the DPF will put the truck in limp mode and only give you a limited number of starts. A race tuner is required. Sct 3015R, 9625OR or H&S mini maxx race or XRT Pro. Several of the vendors on here have stock left of the race tuners.
I have an extra 9625OR with canned tunes laying around if you want it. PM me for price