The difference is as follows. The multitronic is a CVR Continuous variable ratio. Its a chain drive configuration that means you dont feel a gear change, it adjusts the ratio dynamically. It is a very smooth drive if you switch to manual mode it has software configured gears (either 6 or 7) so will simulate a gear change. I have owned two multitronics the first a 2.4 V6. If you floor it, the rev counter goes to the red line then the speed continues to increase with no dip or gear change and the revs stay constant. I now have a 2.0TFSI and it drops the revs each time It reaches the red line (I assume this is to take advantage of the turbo). I love the multitronic its beautiful to drive, my only complaint would be pull off. If you need t pull away quickly there is a 1-2 second delay in hitting the peddle and the car jumping off ( a pain at busy junctions) also then engaging reverse if you hit the throttle too quickly its like dropping the clutch on a manual it jumps with a thud, you soon learn not to do this. Sadly the multitronic is plagued with reliability problems and most people will advise to steer clear. The gearbox was originally a sealed unit and maintenance free for the life of the car, now they advise a gearbox oil change every 40K. This costs around £200 and is strongly advised. If you are buying a car with a warrantee then I wouldnt worry. If not check that the oil has been changed at every 40K interval as this will help with goodwill from Audi should it fail? My first one did fail and needed a new ECU, luckily under warrantee, my current one has been fine. I have a friend who has owned his from new and it failed after 5 years 80K at a cost of £5K L. The Tiptronic is a completely different beast, if you have a quatro it will be a tiptronic, these are much more reliable and supposedly very good gear boxes. So if you know the history and have a warrantee I would go for a multi tronic. Otherwise stick with a manual or tip. I hope this helps.