Wots the differencebetween a Kalahari Defender 300tdi motor and a normal earlier model Def motor?

1.8 blowing head gaskets&wearing of head face.water in engine oil.I.R.D unit failure.Clock face fails after a wipe. td4 hard starting,frequent failure of in tank fuel pump,other electric pump at right rear wheel & left under bonnet.5thdoor window cable failureand door lock failure on lft rear...