GasGas:
DVSA is looking for that too.
Much harder to detect though, an egr blanking plate under the original valve isnt always easy to spot as the original gasket is pressed steel anyway and the way some dpf’s are modified by knocking out the filters inside without any cutting and re welding are only detectable by dismantling. ECU encryption once done also makes it (in a lot of cases) impossible to detect via OBD port investigation…