So had my A6 for a short period of time and then one day at 30mph the limp mode engine management light on kicked in, switch off and back on again worked for a day or two but only for a short period. Car went to Audi specialist and diagnosed turbo issues, turbo was sent off for reconditioning, new diaphragm on the manual turbo, new worm drive as it was broken on the electronic turbo. Picked it up and it just doesn't feel right, pick up from junctions there is a lag which is really noticeable after a stop/start take off. This has been an expensive rebuild but it's still not right - I have seen a few issues with these turbos online, new ones fitted by Audi at £6k etc but is this a bubbling problem or what have others experienced? Car has now been at the garage a month!!!