I just answered a guy who was looking at VW 504/507 oils like EDGE 5w-30 to top up SLX II. I told him to add some M1 5w-50 to thicken what he has and change to an A3 or 5w-40 oil because low HT/HS might not cut it. Would you use a low HT/HS in a Audi VSI? I would not.