It's not hard to understand really. The dealers keep forecourt prices high, as Audi and more so RS Audi's are seen as a premium car. Premium car, premium price.
What the sticker price says and what it's true value is, is not always the same. Dealers are out to make as much money as they can. If the trade in price on an RS3 is around £32k, then it's realistic to expect the car to the be advertised for around £37k. This allows the dealer to make some money after any prep required, while still having a bit of bargaining margin to let the customer `get a deal`.
However, as we all know, car price are just all over the place at the minute. Sticker prices are artificially high, as we now live in the `Billy Big ******` era, where bragging to friends, family and colleagues about how much something costs is somehow seen as a right of passage and show how successful (falsely so) you are. All started off with the housing boom !
Plus with the advent of PCP deals, cars are sloshed around in the system for year where no one actually owns it. So someone taking out a PCP deal out on a new RS3 may quickly realise that the £700 a month they thought they could afford just to be seen in the new RS3, now is not so affordable once fuel, insurance etc is added on top. Or their circumstances change. So the car gets back into the system. The dealers advertise it at list (or thereabouts) and waits for the next punter to walk in, who realistically can't afford a £50k+ car, but thinks for a few hundred more than what they are currently paying for their Ford Focus, they can have an RS3 instead. Look at me, I'm successful !!!
I would suspect if the PCP / Lease bubble ever bursts, car prices will very quickly find their realistic values.