As others have said, the DPF bit is up to you, just letting you know my experiences. BTW my DPF is completely intact, in a plastic bag in my garage...
Just a couple of points to note.
I'm fairly sure you won't get the best mpg if you don't disable it, it does use fuel to regen itself.
The DPF is
a restriction in the exhaust so you won't get the best out of a remap with it in place.
As for smoke and soot, my car is exactly as dirty at the back as it was pre removal. Which is fairly dirty
. The only time it smokes is when I really provoke it (hard). The rest of the time it is exactly the same.
The main reason I had it removed was to reduce the number of things that could go wrong, and guess what, it hasn't givien me any trouble at all (I have had to move it a couple of times to get to the lawn mower but that's about it).
As for the MOT, I've read the new regulations, yes, actually read them! and there's no mention whatsoever about DPF's let alone inspection of them. Catalytic converters, yes, DPF's no. My last emissions test was 50% of the strictest limits used for >08 Euro IV regulations.
Oh and obviously I can tell how much lighter the car is without it
Not trying to change anybodies opinion, just letting you know my experiences.