Hello everyone

I've been recently offered a Startech SD4 tuning box for a Grand Cherokee with the 270CDI engine. Ideally I would get a remap but who I talked to did not inspire confidence that they don't just "turn it up to 11" and hope for the best.

Some info for the tuning box: it reads throttle position, engine speed and coolant temp and changes the signal from the MAP and rail pressure sensor, so I'm thinking it's not a simple resistor to change rail pressure sensor value.

Apparently in the US such diesel tuning options are used a lot, with the ones that change boost and rail pressure keeping the same AFR as factory.

Has anyone had experience with this specific box?