Possibly...but you will have to contend with all the problems associated with DPFs:
http://www.carmagazine.co.uk/Commun...ulate-filters-more-trouble-than-theyre-worth/
And I'm told that cars whose DPFs have been removed are likly to fail the MOT in future.
DPF's are a lot less hassle than a Selespeed box. When a DPF goes wrong you only loose a little power, when a Selespeed goes wrong your left stranded in the middle of nowhere with a car that doesn't know what gears are.