I have a digital in-line tuning box for Vauxhall-Opel common-rail diesel engines, made by Bluespark Automotive/CR tech and used by me in my Astra Mark V Sxi 1.7 cdti PS100 for the past year.
You can see exactly the same unit still on Sale
on ebay for £79 plus pp. I won't go into all the tech - you can read it on the original ebay listing under this number: 181047348579 which will tell you all you need to know and give you the makers phone number if you want more.
It has been great for me, more power, smoother acceleration and better low torque. It's as new; am selling because I am getting a company car so I have no more use for it. Five min to fit/remove.
Mine is optimised for the 1.7 Ps100 engine although it should work with any Vauxhall cdti. Call 07400111443