Marcus S.

Didn't see the negative reviews until I had the tuning box purchased.
Anyhow, worked perfect on my car (520d e60,177hp) and turned it into an animal on the road with good fuel economy as there is loads of pull even in 4th gear at 1k rpm.
Can only recommend for same type car as they have obviously sent me a tuning box with processor rather than a resistor in a box.
(if anything changes over the next week, I'll be back to edit)
Update! Have the box installed about a week now & still happy with power increase... mpg calculator seems to be telling little lies as I'm getting about 100 less miles per tank but what do I expect when I keep flooring it. There is a dial and switch inside box for changing perameters if one is not happy with initial setting.