I have had my 3.6 TdV8 L322 for two and half years and recently fitted a Tunit box to it, I did have a teething issue with it as it was not doing anything, I went down to the Tunit dealer and they checked it over and discovered that my model had a weird software program and it was not triggering the Tunit, so they downloaded a new program to it. Now I am not sure how accurate that is but I know the LED was not coming on until 3500rpm which was wrong, it now comes on at 1200 rpm. The upshot of this is I can get 35 mpg on the motorway quite easily. My overall consumption overall, maybe not as much as the claims but definitely enough to make it feel worthwhile, Torque has definitely improved.

Is it worth getting one? Well at the end the day the choice is yours, there are a few options, Tunit or some other plug n play units or go for a custom rewrite, this gives you the option of deleting the egr operation, something I would prefer to have done but funds would not go that far, It is something I might consider in the future though.

Have to be careful with tuning boxes, some take away the built in safety features which means it can destroy your engine... plenty of info if you google... Pete
__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand Sold
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Sold
2002 L322 Vogue 4.4 V8 Epson Green (Fatty Offroader) Sold
-Click for Project Fatty off roader-

I can assure you, you are not getting 35mpg. The "tuning" box alters the signals seen by the ECU, which fools it into thinking it's running more economically

The tunit alters the the fuel pressure rail signal. The ecu still controls all the safety psrameters. And I can assure you the economy is much better. The forecourt pimp has proved it.
.