There are 3 'levels' (for want of a better word) of DIS.
1. Just range till empty - standard on all A4's
2. Partial DIS - MPG; journey time; avg speed etc which is what people are referring to having retrofitted with the new wiper stalk and buttons
3. Full DIS or actually FIS as Audi officially call it which is as 2 but also including bulb out warnings. If you don't have bulb out warnings, like me, you have a LowLine car. To have bulb out warnings you need a highline car. The only difference is one module - the onboard power control module - 8E0 907 279x. The ending letter which could be B, C, E, F etc determines if you have low or highline. The difference between low and high is how lights get their power - in a lowline car they are all fed from fuses - ie directly. For highline cars, all the bulbs get their power from the onboard power supply - this is how they know if they are not working. To retrofit highline you need to rewire the lights, light switch and brake switch. It's a retrofit that is not too well documented - there is a member on here wmccann who has done it and I am starting on it now, too.....