Additional components are to be integrated in an existing vehicle.
Thus, the vehicle has the meaning of a place (where the components will be fitted) and not of a target which has to be achieved.
In my opinion "destination vehicle" is correct and/or acceptable but my colleagues favour "target vehicle".
Thanks in advance for your answers.
Sorry to say, Torsten, but your colleagues -- and the people who replied to your query on Leo -- are correct. "Target vehicle" is the standard expression used in the automotive industry.
"Destination" always carries with it the idea of a journey. There's no journey here, merely a vehicle which is the object of your attention -- that's enough to make it a target.
A quick check on Google reveals 108,000 hits for "target vehicle", but only 518 for "destination vehicle".