Can’t find specific details, but this brochure from 2016 shows the model line up. PDF brochure By 2016, the Q5 2.0 TDI was available in (150PS) and (190PS) engines or 3.0TDI 258PS. All were 7-speed S Tronic transmissions. They need serviced every 38k miles, which is fluids and filters. Seems the 8-speed Tiptronic box was only available on the TFSI models or BiTDI on SQ5. 2014 models may have been different, and the top of the range 2.0 TDI was probably 177PS or there about. 2.0 TDI would be belt driven, so new toothed drive belt and water pump every 5 years or 60k miles. On 3.0 TDI, suspect it’s chain driven and good for life of car, however they can get chain rattle or stretch if not maintained properly. Pretty sure by 2013/14 Ad Blue was fitted to make them Euro 6 compliant. So you’ll have EGR, DPF, cats, etc. Car needs to have been serviced regularly. If it’s been on a daft 18k long service intervals, or missing history, walk away. Real life mpg, basically these are heavy 4x4 SUVs who don’t expect anything mind blowing, probably 40-50mpg in summer, worse around town, and during winter. The difference between 2.0TDI and 3.0TDI is power delivery and low end torque. If you plan to tow, then 3.0TDI would be a good shout. With all diesels, then they don’t like short run trips or you run the risk of clogged DPF and EGRs. As long as they are doing long trips too to help DPF regenerate, that will keep things ticking over. Use a can of Forte fuel conditioner on nearly empty and change the fuel filter afterwards (every 20k miles), plus Forte anti-crystal on every AdBlue top up. I’d also say use premium diesel. Do your research before parting cash. Also consider VCDS to scan any prospective car. This holds all fault codes unless they have been cleared. Very useful tool down the line if you DIY service, fuel pump, rear electro mechanical brake reset, etc.