After running a £50 German Ebay-sourced analogue tuning box on my 110bhp A4 for the last 2 years I was of the opinion that they are all the same really............ Well, I was wrong! Bought a bargainously cheap s/h digital Dragon Performance box on Ebay the other week and have had it on there for the last week or so........... The difference is amazing! No more plumes of black smoke when giving it some welly, the increase in torque really noticable, and whats more, over a 260 mile test (couldn't wait to re-fill tank to see economy I was getting) it did 50.3 mpg, thats a mixture of motorway/ urban and fast A-road traffic, up from 46-47 with the old box fitted. To say I'm impressed with it is an understatement, if there are other A4 owners looking at Dragon modules I'd say go for it, they even responded to my email about a request for fitting instructions for mine within the hour, as mine didn't come with any!