I'm thinking of upgrading the 2.0d with a chip that claims giving me 170 bhp and a bit more torque. Will it be necessary to upgrade other parts aswell?

 

I am sure that others will chime in but if it is too good to be true it probably isn't. If you do a search about mapping the ECM or programming the ECM you will find that there is not any support for our controls. If changing a chip would do it you would see it all over the site. More HP equates to intake, exhaust, and ECM controls. I have a 3.0 and I am planning to see just how far I can push it, headers, cold air intake, (maybe) turbo with a piston change and definitely a new exhaust.
Good luck in your quest for HP

 

Have you considered remapping?