I have a tuning box on my 1.6 TDCI and it transforms the vehicle, I mean it was fairly smooth and powerful to begin with but with the box on it pulls very easily from 1000rpm which has so far done wonders for the fuel economy.
The increase in power is amazing, right upto 4000rpm it will pull very strong but its the in gear acceleration that has improved the most, 50 to 70 in 4th gear timed roughly at 4.7 seconds.
The only fly in the ointment with a tuning box on this engine is its an absolute ball ache to fit as PSA in their wisdom decided to hide the common rail plug under the fuel filter in between the rear of the engine and the bulkhead.
Of course tuning boxes are cheaper than remaps and in my case hasn't needed any modification to the DPF, but there will always be those owners who swear remaps are safer than boxes because all they do is falsify fuel data to the ecu bla bla.
Im currently looking at employing a remap to go with my tuning box
so how many more 320d's I can embarrass!