Look up the terms "Audi" and "repair" on YouTube for an introduction to the pain of Audi ownership. Finding a mechanic willing to work on your Audi will be a challenge because they're so legendary for being expensive trash.
As for the Caddy, it's hard to justify paying the same amount for a possibly-medium-quality vehicle as you could pay for a top-quality vehicle such as the Lexus suggested above. I would go further and evaluate whether you get any extra benefit from the Lexus/Acura/etc. luxury nameplate than you'd get from a loaded car with the parent company Toyota/Honda/etc. nameplate.
As
@travel2020 notes, you can get slightly used luxury vehicles for a massive discount. It is the "newness" that people pay an extra five figures for and this is especially true for status symbol vehicles. If you're buying for the comfort factor, used is just as good.
Finally, I suggest digging into certain quality details:
-Does it have a cone-and-belt CVT transmission? If so, avoid!
-Does it have a plastic oil pan and/or camshaft cover? Probably a sign of low quality.
-Does it have a timing belt, rather than a chain? If so, avoid unless you like doing $2k maintenance every 100k miles.
-Consider the hybrid models. They tend to have better transmissions, drive more quietly, and the engines last longer.