Yep, it is
one of the correct options.
Many people will recommend going for 5w30 and see it as am 'upgrade', however I would recommend staying with the 5w40
Among other reasons.. I recommend staying on 5w40 and not changing to 5w30 as this would be counter intuitive to provide the correct protection - on a simple basis as an engine ages/wears gaps increase rather than decrease and so any change in oil in terms of protection would be better served by increasing viscosity rather than decreasing as would be the case with 5w30.
This assumes that the engine wears out beyond the ability of a 5W-30 to 'fill the gaps', which is highly unlikely. Besides, what gaps are we talking about? The crank journal bearings are essentially self-filling, so will entrain oil as they rotate and generally operate in a hydrodynamic mode so all they need is a good supply of oil, which the pump provides. Ring/liner contacts are most critical at top-ring turnaround, but with liner and ring plating these days they don't wear a lot and the different in viscosity between a 5W-30 and 5W-40 at top ring reversal temperatures will be pretty small. Cam-on-follower is the highest contact stress but these rely as much on surface protection additives as viscosity.
...(or sticking with original spec)
Factory-fill oil is/was...?!
(although not really a major concern between 5w 40 and 5w30, oil pump rates and other concerns should be considered if making significant changes to viscosity used).
Yes, sort of, but oil pumps are positive displacement type so will push the same volume regardless of the viscosity. How well this then permeates the various working parts of the engine can be a factor, but at working temperature there will be pretty much no difference between a 5W-30 and 5W-40, given that the engine has to work and not wear out during warm-up, when the oil is far thicker anyway.
With regular 6 month oil changes, good quality semi synthetic would likely be perfectly fine, as the main drawback would be degredation over time, but with 6 monthly changes ithis is not really an issue. (even at 12 months is not a notable issue)
However it is clear than synthetic oils do offer better protection over a wider operating window and so synthetic oils are the better option. (but do look for good quality so its a true synthetic) id prefer a longer 9 month change with better quality oil than 6 monthly with a cheaper oil if cost is a concern..
I advise it is best to stay away from how the oil is described in terms of semi- or full-synthetic and focus more on what performance it gives. This is demonstrated by the specifications and approvals it holds*. VW's specs are well-known challenging specs to achieve, so a 5W-30 that has reached this level has had to include some decent base oils and additives simply to jump this hurdle. Oh, and some 0W-30s are approved too.
Don't get me wrong, a 5W-40 meeting 502 00/505 00/505 01 is a decent oil and good for these engines, I just wanted to put across a bit of extra food for thought to at least not worry anybody running 5W-30 or 0W-30 (which is also a decent choice).
*Read data sheets and labels carefully - some say something like "meets the requirements of ..." or "suitable for use where ...... is specified". This often means that the oil is not formally approved by the OEM in question, but the oil maker has made a judgement call. It is quicker and cheaper to do it this way, but without a formal approval the OEM can offer no support, if needed.