I had a 2014 A3 1.8L TFSI, then a 2016 A3 2L TDI which I remapped to around 210bhp. Was looking for a 2017/18 Q5 and originally was planning on getting a well specced 2L TDI but then I found out they did a 3L TDI (286BHP so equivalent of a 50TDI) and set my heart on that. I managed to get a reasonably well specced 18 plate (comfort pack, tour pack). Not quite as powerful as an SQ5 but it certainly shifts, think it's 5.8s 0-60. I think they stopped making them after the 18/68 plates but I could be wrong.
I've hit 55mpg on a motorway run, albeit with some sections of slower speed restrictions obviously helping, my long term average since I had it is 40.59mpg. Most of my driving is 60 mile round trip for work, do the odd short trip to town.
I think they're quite a rare model so you may need to be patient but I honestly don't know what I'd 'upgrade' to as it'd be a very hefty spend to go up a level in terms of spec/quality of car imo.
