Hi Warren.....welcome to the Forum
I have previously owned a Tuning Box (on a Honda CRV 2.2 cdti) and unfortunately sold it when I sold the car. It takes about 10 -15 minutes to fit yourself.
However, in the time that I have it fitted, it vastly improved the driveability of the car, made it more flexible on the transmission (didn't need to change up constantly to maintain road speed), the economy improved by at least 15% and quite frankly cried when I took it off....what a difference it made!
I fitted it with the intention of improving the economy and this is exactly what it did....I didn't however, buy it with a huge performance increase in mind.
I would say, go for it, you won't regret it !