Wow- this is an old thread - i came across it looking for something else!
The (Mondeo mk3) TDDI and TDCI are basically the same, the TDDI 115 uses a Bosch VP44 pump and mechanical injectors (non- common rail), the TDCI is a common rail engine that uses delphi electronic injectors, the engine internals (2.0L) are the same , including cams/ chains valves etc etc the cam chain/ tensioner valve gear is very reliable, does not require frequent changes, and can last 300K+ miles with regular oil changes
A good tuning box is just about as good as a remap, in fact the DTUK tuning box i use has more bottom-end grunt than the Superchips Bluefin remap i also run, they both cost about the same (approx £400 when 1st released and about £320/£330 now/ or with discount) you get what you pay for and a cheepo "resistor" tuning box is obviously not the same thing, or a dodgy "back street" remap that they got off the net installed by someone who dies not know what they are doing
159Hp from an otherwise stock TDDI (or 178Hp from a TDCI)is unlikely/ unrealistic, most digital tuning boxes claim 140-145Hp, and the Superchips Bluefin remap 147Hp, to get 159+, requires a bit more work.....
If you want to know how to get 160+HP out of your 2.0l TDDI, read my build thread,