No need for three duplicate posts, the extras have been deleted.
Can't help with Diesel questions without researching it myself, that type isn't sold here.
Some general advice would be to research tuning more, as the only type that works on any I DO have experience with is similar to tuning a petrol engine. You need a flasher to change tuning in the ECU to have any real benefit.
A 'box" that attaches to a pressure sensor would be like a "chip" that works in a similar way for petrol engines - not worth consideration since they don't work as described as a general rule. Trying to fake out the system isn't a good way to attempt 'tuning" with better options available.