It can be done DIY, but you need decent height clearance. Personally, find an independent with a lift and use OE fluids.

Yes, but then water pump went first, replaced with new belt and timing done. Battery when charged is about 13.8v, don't know how old it is. After that I had 4 faults on OBD reader, don't remember codes but a local mechanic point it to EGR Valve. The rest came after simply by Google and pointing to what it could be

Many thanks. That's really reassuring. I shall stop being so sensitive! Is this a DIY job?

If this is your first quattro, then I'm inclined to say it's probably known characteristic. They don't particularly like hard lock to hard lock, so avoid where you can. If the rumble continues on straight road, thats different. You can double check CV boot gaiters, just to make sure there's no tears. If it's a bearing, you'll hear a constant drone noise around 50mph. Regards diff, 218hp is 160kw and likely to be standard mechanical differential. You could go under car and see if there's a part number. All the build codes for the car can be entered into a VAG decoder, which may reveal more. Wouldn't do any harm to change the, centre diff gear oil. Audi will say sealed for life, which is nonsense of course. I'd change rear diff fluid too. Regards 3.0 engine, it's generally bullet-proof, however to get the best out of it, get into routine of regular oil chances every 5-8k miles. Its chain driven, so damaged guides, or a stretched chain (chain slap/rattle on start up), then you're looking at expensive repair. Assuming is S Tronic gearbox, then transmission fluid needs changed at 38k miles.

Dear All and thank you, Brian, I took your advice and changed to 35 psi, and it appears to have improved the ride not considerably but certainly noticeable. As Cliff mentioned 33psi may be too low and incur tyre wear, so hopefully this is a realistic compromise. Reading the posts it appears the Q3 S-Line is a harder ride than my previous Q5, so I guess in a month or so I will have grown accustomed to it. Had an odd one this morning, tried to open the boot, but it only opened about 6 inches. Tried unlocking and locking the car but still the boot would not open so had to open it by force manually. Pressed the boot lower button, and it closed OK and then opened OK - very odd. Then to further confuse the radio sound would not work but worked on the USB. I googled, and it said it was a fairly well reported issue and to do a 'reset' which fixed the issue. As much as I like this car it has some annoying traits !!🤐