What’s worth doing to an S8 D3?
 

So far I’ve got a VCDS cable and lowered the suspension slightly, updated the MMI to 5570 and I’m planning to replace 2 naughty Parking sensors so my park assist works, adding a BT module Dension? And replacing the exhaust with a custom made Vortex system (Cat back, no resonators and 2 Vortex chambers)

Is there anything else I should do?

Not much you can do in the way of tuning or making it go faster really, but could be worth investigating the state of your intake manifold flaps if they haven't been addressed before, and whether your ports are coated with carbon build up - a charming characteristic of FSI engines. Will be worth addressing from 70,000-80,000 miles and there are lots of threads on the forum about it. Just had mine all done and it's like the engine was being strangled compared to what it feels like to drive now.

Some common problems crop up every now and again. Water ingress due to blocked drain points, leaking washer fluid bottle, soft close motors packing up if you have them on your S8, that's about it. +++

Tinkering with the exhaust is a must though, it's so muted and restricted from factory. Even just tying the butterfly valves open on the back boxes improves things immediately. Removing a pair of the centre silencers improves things further (which I got done at a place I can highly recommend in Romford), and that's where I stopped with the exhaust as I wanted to keep the stock tailpipes and get a nice burble at low speed but full V10 symphony when my right foot is down. Other members have gone with full cat-back Milltek systems.

Cheers for that, I’m not fussed about going faster really (it’s a family wagon)
It’s just hit 70k so I’ll be looking at getting it cleaned, de-flapped and re-mapped after I’ve had my exhaust fitted.
I have got soft close but they have all died, not to bothered though, I heard they go quiet often so I’ll leave them.

I changed 2 of my parking sensors this morning ( Front right and back right) and now the park assist works but my camera has no picture, is that related to the Hybrid TV tuner as that is missing- does the camera connect to the aux in on the Tuner?

A missing TV tuner shouldn't affect it. The TV connects to the back-up cam module and it's this module that controls the switching between TV and parking signal. It's located in boot left side towards the back if you need to find it.

Feel free to post a full VCDS scan so we can take a look and give you any pointers to issues, there's a wealth of knowledge on this forum.

Thanks Matt, I’ll get a scan done next time I’ve got the cable connected.
Today I locked my exhaust flaps open and it sounds so much better! I also managed to get my Bluetooth working but it seems to disconnect after around 10 mins, is that a know issues and how can I fix it?