Hi Jon,
I 'adopted' my first Audi last March, having been a Ford man all my life so far... And as long as I can afford them, I will never go back!
As far as what to maintain - I'm new to that too, so will leave others more qualified/experienced to answer that... I can tell you that mine also has 120k, had a full Main Dealer Service History with previous owners, and I'll be sending it off for a 'Full Service' - to include all fluids in all components along with the usual service items - just for my own peace of mind. One thing to note is a common fault, apparently, with the 3l V6 TDI's - there is a plastic valve on the top of the engine 'in the V' between the cylinder heads, that can perish and start leaking... Don't know too much about it other than mine has the issue, so my coolant level is consistently lying just below Minimum on the expansion tank and has to be refilled if I've parked it on a slope! So mine will also be having that replaced at the same time - £30 for the part and near £600 for the labour as they have to remove everything to get to it, apparently! So one to watch for...
Regarding remaps; I was quite disappointed that mine was not achieving the figures given in the specs - not even close! I know they're a guideline, and rarely meet real world, but still I wanted to optimise it... So I went for a Superchips/Bluefin remap - literally online order, equipment shipped to you, DIY. And the difference was startling!
I have a 2017 A6 after the 'facelift' with the 272PS engine, so 268BHP when new in theory... The figures given for mine on the Superchips website are:
Manufacturer claimed BHP & Torque
268 BHP & 585 Nm (432 ft lbs)
After Superchips Remap
334 BHP & 688 Nm (507 ft lbs)
So, in theory, a gain of 66 BHP and 103 Nm (75ft lbs)
I have not measured it - either before or after - so cannot verify the figures. What I can tell you is that I now get at least 3mpg better economy, even with a relatively heavy right foot - even more so in 'economy' mode. And from the lights I can now beat RS4's & RS5's - much to their anger and disappointment when it says A6 TDI on the back of mine!
So, in conclusion, I would say the Superchips remap is worth it! (Other brands, obviously, are available)
https://www.superchips.co.uk/ECU-Remap/Audi/A6-Avant-C7-2011/Diesel
Best Regards,
Tigger