So looking at the brochure the 428d has the 2 litre diesel lump and the 435d has the 3 litre diesel lump I can't find the reason why they are different numbers. The only difference I can see is that the 435 is the 6 cylinder engine whereas the 430 is the 4 cylinder. OK I get that but then the 420 and 428 are the same engine, so anyone care to hypothesise on this?