chimaera

That's irrelevant! The manufacturer has specified 16" as the minimum, end of discussion.

Perhaps, but the list of type approved wheel sizes only lists 16" and higher for the Superb 2.

So, as best as I can figure out, the front diff shares oil with the rest of the DSG 'box. The angle gearbox for the 4x4 system has its own oil fill, and it uses the same oil as the rear final drive, not sure about quantity, but probably in the region of a litre. It requires the same special fill tool that's used for filling the DSG itself. I would strongly recommend sticking with the OE oil for the Haldex unit and the DSG. Both of these have wet clutches that depend on the oil to work properly. Cheaping out here will cost you thousands down the road. VAG lubricants are cheaper than people realise. Before the Superb I had a B5 Passat (ordinary 5sp manual) and I did a gearbox oil change with standard 75W90 gearbox oil, and it was only ever so-so. A while later I got the proper VW oil from a dealer (around €13/l IIRC) and it was a night and day improvement in shift quality. You will also need the special fill tool for the DSG and angle gearbox as they use a single drain/fill hole on the bottom, and you need the tool or an equivalent to refill them without spilling oil all over the place.

2.0 TDI gets 312 mm disks on the front. 15" wheels are not type approved for the Superb 2.

Clunking when taking up drive is often a sign of a worn DMF. Another telltale is clunking if you release and re-apply the accelerator, especially uphill. Mine is doing this, and I've started saving for the replacement.

Yes, it depends on the engine.

The lighting characteristics of an LED bulb will be different to those of the specified halogen bulbs. You will probably get less usable light on the road and cause more glare for other road users. Stick with the halogen bulbs the headlamps were designed to use.

I think the front final drive shares the same oil as the rest of the transmission. I'll double check later.

Generic oils don't tend to be great in VWs. I've posted the VAG part numbers - you can cross reference against those.

Have you checked that the Haldex unit has been properly serviced up to now?

Have the suppliers specified what strength the 150 mm of concrete should be? Do you then know what strength was used on your garage floor?

Rear final drive takes 0.925 l of oil. Haldex coupling takes a maximum of 0.85 l of oil, but the refill amount is listed as 0.72 l. Capacity for the DSG is up to 7.2 l but the service manual lists 5.2 l as the replacement quantity at service. You will need a special tool to refill the gearbox, tool is VAS 6262 or 6262A. You will also need VCDS to check the gearbox oil temperature during the refill process. For the refill especially, the car must be level, so putting the car up on axle stands at the front is not going to work. Oils are: Rear final drive: G 052 145 S2 Haldex Coupling: G 055 175 A2 DSG: G 052 182 A2 If you are looking at aftermarket oils, make sure they cross reference to those part numbers. I've seen a few threads here where owners have documented doing the DSG service themselves, and the general consensus has been this is one that's best left to a dealer or a good indy, as the savings are marginal by the time you have purchased oil and the tools needed. I've scanned through the service procedures for the different parts and TBH I'd probably leave this job to a mechanic, if only because it looks like a pain in the arse and requires a bunch of special tools for the different drain and fill procedures. If you're really keen on doing this, I'd suggest you head over to https://erwin.skoda-auto.cz/erwin/showHome.do to grab the service manuals for the car and have a good read through them before you think about doing this.

Any diagnostic scan?

No, the point of the system is that it prevents you from exceeding the posted speed limit. You can't travel faster than the system allows. Over-rides seem to be an option only in the early stages of roll-out to allow for transition. I had a feeling you might deliberately misconstrue the point in relation to rear-ending: my point is that the system could fail in a manner that would force the vehicle's speed down to something much lower than the traffic around it, leaving other cars no time to react to avoid it. As an engineer I look at systems like this from the point of view of how they could fail and how that might be problematic. The fundamental point is that a system out of the driver's control is now controlling the vehicle: is the owner of that system willing to accept the liability that comes with that?

No. If it's a system internal to the vehicle then it's up to you as the owner to ensure your vehicle is maintained and in good order; you may have recourse to the manufacturer of the vehicle or parts on it in the event of a breakdown but ultimately it's your vehicle, your problem. ISA is a system that requires external roadside infrastructure and systems (that are not within the driver's ability to inspect or maintain, nor under the driver's control) to interact with the vehicle in order to control aspects of its operation independently of the driver, without the driver's knowledge or consent. And before you ask, no this is not the same as failure of traffic lights or other traffic control measures, as they rely on the driver's interpretation and action to have any effect on the car. ISA bypasses the driver and directly controls the vehicle. My point is to ask whether the governments implementing this system are willing to assume responsibility for the operation of their part of the ISA infrastructure and any failures it might run into e.g. a car is forced down to a speed of 50 km/h on a motorway and gets rear-ended because it's suddenly going at less than half the speed of the traffic around it. I have no doubt the system is engineered so that a complete failure of the roadside infrastructure would result in the vehicle system falling back to manual control by the driver, but the danger is that the roadside infrastructure would partly fail and give incorrect signals to vehicles: in this case the vehicle system sees a valid message arriving in and obeys it because it has no reason to think there's a problem, and the driver does not have the option to override it.

Is any government willing to take on the legal responsibility for the situations where it malfunctions or restricts speed inappropriately? Because if they take control away from the driver, that's what they're committing to.

Hmm. Any bangs or knocks around the front of the car recently? Anything shoved out of place? Check the adjustment of the bump stops - if they're too high they'll prevent the latch from closing properly.

If possible, find a roundabout/slip road nearby that'd allow you get onto the other carriageway so that you can leave to the left onto the road you want to take?

Is the release cable moving freely within the sheath? If that's sticking, it could be preventing the catch from getting into the locked position.

It's a nightmare and hitting right across the board! We're having to redesign the main PCB for products where I work to circumvent shortages on a lot of pretty mundane parts on it. I can only imagine the problems the car industry is dealing with when you consider the number of control modules a modern vehicle has.

EN 228 specifies that ethanol used in petrol must meet EN 15376 which has a limit of 0.3 % mass fraction of water in the ethanol. Benzene is permitted in petrol up to a volume fraction of 1 %, so a certain amount of residual benzene in ethanol could be ok, depending on the aromatics content of the base petrol used. These days there are also processes that can achieve very low water content in ethanol for motor fuel use without the need for extractive distillation, but it's too early in the morning for me to go reading up on them in detail

The OE is Sachs IIRC. All modern shocks are gas and oil filled, so it's just down to individual brands in how they put them together.

You need to check the mechanical alignment of the headlights, not just adjust the angle within VCDS. The adjustment mechanism in the AFS system has a limited range of movement, and if the mechanical setting of the headlamp is off, there's a good change the AFS controller will run into situations where it can't adjust enough to correct the beam. You will need diagnostics to put the headlamp controller into 'Basic Settings' mode (this puts the AFS adjusters into the centre of their range) and then use a standard beam setting tool to adjust the position of the headlamp to the appropriate position. That is what ODIS and VCP are.

I suspect some part of the airbag system has detected a collision and it has gone into crash mode. IIRC VCDS can't do much in these circumstances, something like VCP or ODIS is needed to reset the airbag ECU once any damage has been repaired. @langers2k knows a fair bit more than me about diagnostics, he might be able to offer more insight here.

Replacing anything that's badly worn is going to feel like a night and day difference no matter what you put under the car.