I'm an avid motorsport 'fan' and avid viewer of many and varied categories and....I couldn't name one series they race in. (Edit: To clarify I mean entered as VW)
I would argue that they're already wasting money on motorsport, because if someone who watches a reasonable amount of motorsport has no idea what they race and promote their wares in, then Joe Public and his £££ certainly ain't being reached.
This is a genuine guess at what they're involved in, whether as a factory entry or supplier:
* Paris to Dakar (their's is the big red/blue truck thing I believe).
* A Scirocco (can't be arsed to check spelling) series.
* Truck racing???
* A wee dabble in WRC or they recently entered/returned?
I'm fairly sure they don't race in BTCC, although I tuned out about two years ago. DTM....I don't think so....
I'll tell you this for free: I'm pretty sure they used to badge British F3 at some point over the last 10 to 15 years....but I don't think the engines were even theirs.
Pure guesswork.
I realise this evidently includes Audi. But perhaps proves a point that it'll have zero public perception on the Audi brand.
QED.
I took the liberty to include the group here to give you a nice little image.
World Rally Championship - dominates the WRC with the VW Polo WRC
DTM - Compete with Audi
WEC - Compete with Porsche
GT3/GTE - Compete with Porsche as well as selling cars to customer teams
Touring Car International - sell Seat Leon TCR cars to customer teams as per regulation. A VW Golf TCR has just been debuted, run by Engstler Motorsport
BTCC - privateer team racing with VW Passat with some VW backing
Seat Leon Cup - European one make cup with Seat Leon. In addition there is a Skoda Octavia Cup in Czech and a Easter European VW Golf Cup.
World Rallycross Championship - Two official factory VW teams competing with official backing, run by teams with VW backing. In addition there are also Mattias Ekström Audi team, also with official backing.
Global Rallycross USA - official factory team in US as well, the VW Beetle, with Andretti Autosport
Asian Rally - A VW Golf made for rallying in China by Prodrive with support from Volkswagen
Formula 3 - Official backing as engine supplier
Volkswagen Group is quite active in motorsport with all its brands including Volkswagen and you really have to include WRC and World Rallycross as high end factory programs with the Volkswagen brand.
And there's probably more I've missed.