Service history is a must above all really. They're solid cars as long as they are serviced properly. If the gearbox service hasn't been done by Audi or a decent independent at the 38k intervals I'd run away. The V8s prior to the 3.0 supercharged units were notorious for coking up, but you say it has an uprated pulley which suggests the 3.0 supercharged power unit which is great as they are massively understressed units. A S/C pulley, a breathier airbox and a remap will easily put them into 4 seconds 0-60 times without really putting any stress on the running gear and can be had from a reputable Audi tuner for £1,500 max. As to the sunroof, that could be a costly affair but I guess it depends on how often you open it. I would personally favour a non-functional sunroof just because it makes the interior of the car feel much airer. You never know, you may get lucky and the runners just need a decent greasing - a burnt out motor or similar is going to be expensive though.
With the Audi Drive Select, this can be 'enabled' with a £20 adapter from Amazon. In fact there are loads of options you can enable through software on VAG cars, but if the car wasn't factory optioned with the magnetic steering and adaptive dampers (i.e. the hardware to interface with the software), it's a total waste of time as all it will do is control the volume of the piped in engine noise.
I just dumped my 2015 S5 for this hilarious financial burden that people seem compelled to park their ****boxes right up against in empty car parks. Three weeks in and the dashcam is like 48 hours worth of footage of me laughing like an idiot.
Yeah, it's an early 3.0 V6 rather than a V8.
I know it's had one DSG service, and he's said he was going to book it in for another one if he was keeping it, so it must be due soon.
I've got a Carista OBD adaptor that I've used with my Cupra, hopefully it would be compatible with the Audi too.
Thanks for the detailed post, very jealous of your new toy?