I have commented on this scores of times. DPF removal is illegal under EC Type Approval and Emissions regulations because it modifies the car not to meet its certified emissions on the basis of which it is taxed. The fact that VOSA in the UK does not currently enforce this in the MoT does not mean that it will not in the future. Nor does it mean you could not be stopped in a roadside VOSA check and have your car taken off the road for not complying. If you don't disclose the modification to your insurer your car is automatically not covered (though third party damage has to be). And, if it felt so inclined, HMRC could pursue you for tax evasion. So anyone thinking ore removing their DPF needs to be aware of the potential consequences.